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Digitized  by  the  Internet  Archive 

in  2009  with  funding  from 

Boston  Library  Consortium  IVIember  Libraries 


http://www.archive.org/details/dinoceratamonogrOOmars 


DEPARTMENT   OF   THE    INTERIOR 


MONOGRAPHS 


United  States  Geological  Survey 


YOLUME    X 


WASHINGTON 

GOVERNMENT    FEINTING    OFFICE 
1886 


/v\7 


UNITED   STATES   GEOLOGICAL   SUEVEY 

J.  W.  POWELL,  DIRECTOR 


DINOCEEATA 


MONOGRAPH 


EXTINCT   ORDER  OF  GIGANTIC  MAMMALS 


OTHNIEL  CHARLES  MARSH 


WASHINGTON 

GOVERNMENT     PRINTING     OFFICE 
1886 


United  States  Geological  Survey, 

Division  of  Paleontology, 

New  Haven,  Conn.,  December  18,  1884. 

Sir: 

In  compliance  with  your  letter  of  instructions,  dated  October  5, 
1882,  I  have  the  honor  to  transmit  herewith  a  Monograph  of  the 
Dinocerata,  an  extinct  order  of  Mammals  discovered  in  the  Eocene 
deposits  of  Wyoming  Territory. 

Very  respectfully, 

Your  obedient  servant, 

0.    C.    MARSH, 


Palceontologist-in-  Charge. 


Hon.  J.  W.  Powell, 

Director  of  the  U.  8.  Geological  Survey, 
Washington,  D.  C. 


TABLE     OF    CONTENTS. 


Title  of  Volume, .-. iii 

Letter  of  Teansmittal, v 

Table  of  Contents, vii 

List  of  Illustrations, ix 

Preface, xvii 

Intiiouuction, 1 

Chapter  I.            The  Skull, 11 

II.           The  Lower  Jaw, —  35 

m.         The  Teeth, --  41 

IV.  The  Brain, -.. 53 

V.  The  Cervical  Vertebra, ..- 69 

VI.  The  Doeso-Lumbar  Vertebra, 19 

VIL        The  Fore  Limbs, 87 

VIII.  The  Fore  Limbs  (continued), 101 

IX.  The  Riiis  AND  Sternum, 129 

X.  The  Pelvic  Arch  and  Tail, 135 

XL         The  Hind  Limbs, 139 

XII.  The  Hind  Limbs   (continued), . .  145 

XIII.  Restorations  of  Dinoceeas  and  Tinoceeas, 165 

XIV.  Conclusion, 169 

Appendix. — Synopsis, 193 

Bibliography, .._ 225 

Postscript, 237 


ILLUSTRATIONS. 


LIST     OF     PLATES. 

Plate  I Skull  or  Dinoceeas  mirabile. 

"       II .. Skttll  of  Dinocebas  mirabile. 

"       III Skull  or  Dinoceeas  mikabile. 

"       IV ... - Skull  of  Dinoceeas  mieabile. 

"       V Skull  of  Dinocekas  mirabile. 

"       VI Bi:ain-cast  of  Dinoceeas  mirabile. 

<'       VII • MoLAES  of  Dinoceeas  mirabile. 

"       VIII.-- --- --- LowEE  Jaw  and  Teeth  of  Dinoceeas  mieabile. 

"       IX -- Teeth  of  Dinoceeas  lucaee. 

"       X Skull  of  Dinoceeas  laticeps. 

(■       XT .-.    -   - Skull  op  Dinoceeas  laticeps. 

«       XII LowEu  Jaw  of  Dinoceeas  laticeps. 

"       XIII --- LowEE  Jaw  OF  Dinoceeas  laticeps. 

"       XIV Skull  of  Dinoceeas  laticeps. 

"       XV Skull  of  Tinoceeas  ingens. 

"       XVI Skull  of  Tinoceeas  ingens. 

"       XVII .  -  - -  -  - Skull  of  Tinoceeas  ingens. 

"       XVIII Teeth  op  Tinoceeas  ingens. 

"       XIX LowEE  Jaw  a-nd  Teeth  of  Tinoceeas  pugnax. 

"       XX -   --  Atlas  of  Dinoceras  mieabile. 

(•       XXI - Axis  of  Dinoceeas  mii; abile. 

"       XXII --- Ceevical  Veetebr2e  of  Dinoceeas  mieabile. 

"       XXIII..- Doesal  Veetebe^  of  Dinoceeas  mirabile. 

"       XXIV Doesal  Veetebrje  of  Dinoceras  mieabile. 

"  XXV --  LuMBAE    VERTEBEiE    OP    DiNOCEEAS    MIEABILE. 

"       XXVI LuMBAE  Vertebeje  of  Dinoceeas  mieabile. 

"       XXVII. Left  Scapula  of  Dinoceeas  mieabile. 

"       XXVIII. -   - Humerus  of  Dinoceeas  mieabile. 

"       XXIX Radius  op  Dinoceeas  mieabile. 

"       XXX Ulna  of  Dinoceeas  mieabile. 


X  ILLUSTRATIONS. 

Plate    XXXI Scaphoid  and  Lunar  op  Dinoceeas  mikabile. 

"       XXXII Pteamidai,  axd  Pisifoem  of  Dinoceeas  mirabile. 

"       XXXni Teapezium  and  Teapezoid  of  Dinoceeas  mirabile. 

"       XXXIV..- Magnum  and  Unciform  of  Dinoceuas  mirabile. 

"       XXXV Metacarpals  of  Dinoceeas  ihrabile. 

"       XXXVI --- Metacarpals  op  Dinoceeas  mirabile. 

"  XXXVIT MliTACAEPALS    OF    DiNOCERAS   MIRABILE. 

"       XXXVIII Phalanges  of  Dinoceras  mirabile. 

"       XXXIX Ribs  of  Dinoceras  mikabile. 

"       XL _  Sternum  op  Diniiceras  mirabile. 

«       XLI -- PisLvis  OP  Dinoceeas  mirabile. 

"       XLII Pelvis  of  Dinoceras  mirabile. 

"       XLIII.    Caudal  Vertebrae  op  Dinoceeas  laticeps. 

"       XLIV Femue  op  Dinoceeas  mirabile. 

"       XLV. Tibia  of  Dinoceeas  mieabilic. 

"       XL VI Fibula  and  Patella  of  Dinoceeas  mirabile. 

"       XLVII. -- Astragalus  op  Dinoceras  mirabile. 

"       XL VIII Calcaneum  op  Dinoceeas  mirabile. 

"       XLIX Cuboid  and  Naviculae  op  Dinoceras  mirabile. 

"       L Tarsal  bones  op  Dinoceras  mirabile. 

"      LI .. Metatarsals  op  Dinoceras  mirabile. 

"       LII. Metatarsals  op  Dinoceeas  mirabile. 

"       LIII Phalanges  op  Dinoceeas  mieabile. 

"       LIV Feet  of  Dinoceras  mirabile. 

"       XjV --•  Restoration  of  Dinockras  mieabilk. 

"       LVI Restoration  op  Tinoceras  in  gens. 


LIST    OF    WOODCUTS. 

INTRODUCTION. 


Page. 


Figure    1.  Map  showing  region  of  Z'mocej'fts  beds,- . 3 

"  2.  Section  to  illustrate  vertebrate  life  in  America, 1 

CHAPTER     I . 

Figure    3.  'Sa.s^s  oi  Dinocer'as  mirciMle, 13 

"  4.  'Na.sdls  oi  Dinoceras  distans,.  ... 13 

"  5.  Nasals  of  Tinoceras  pugnax, 13 

"  6.  'Sa.saXs  oi  Tinoceras  aniiectens, ' 13 

"  1.  Sknll  oi  Dinoceiris  mirabile,  with  brain-cast  in  position, 15 

"  8.  Skull  of  young  specimen  of  Dinoceras  distan.i, .  15 

"  9.  Skull  of  Tinoceras  zw^e«s,  with  brain-cast  in  position, 16 

"  10.  Skull  of  Dinoceras  distans^ '16 

"  11.  Skull  of  Uintatherium  latifro)is, J7 

"  12.  Skull  of  Tinoceras  vagans, .. 17 

"  1 3.  Posterior  surface  of  skull  of  Dinoceras  mirahile, _.  19 

"  14.  Posterior  surface  of  skull  of  Dinoceras  laticeps., _- 19 

"  1.5.  Posterior  surface  of  skull  of  Z>««oce«ys  cr/Zresie, 19 

"  16.  Posterior  surface  of  skull  of  Tinoceras  affine, .._ 19 

"  1 1.  Posterior  surface  of  skull  of  Tinoceras  iiigens, 19 

"  18.  Postei'ior  surface  of  skull  of  Tinoceras  pugnax.^ ^ 19 

"  1 9.  Side  view  of  skull  of  Tinoceras  pugnax, 21 

"  20.  Anterior  part  of  skull  of  Tin oceras  grande, 21 

"  21.  Awtei'iov -pwct  of  skwW  oi  Tinoceras  aim evtens, 21 

"  'i2.  Anterior  part  of  palate  of  Dinoceras  laliceps, 25 

"  23.  Anterior  jjart  of  palate  of  Tinoceras  ingeois, ._. 25 

"  24.  Anterior  part  of  palate  of  Tinoceras  pugnax, 25 

"  25.  AntQviov  Tj)n.vt  of  T[>^\Ate  ot  Hippopiotamus  amp)hiMus, 25 

"  26.  Skull  of  Dinoceras  niirabile;  seen  from  below, 26 

"  27.  ^\\\\\  oi  Dinoceras  laticeps;  seen  from  below, 26 

"  28.  Skull  of  Tinoceras  ingens;  seen  from  below, 27 

"  29.  Skull  of  7'«!0cer«s  jOM(///aa7  seen  from  below, 27 

"  30.  Horizontal  section  of  skull  of  Tinoceras  crassifrons, 29 

"  31.  Horizontal  section  of  skull  of  J? i/iOf'cras  (??sto«s, : 29 

"  32.  Horizontal  section  of  skull  of  ^Vnocfras /«■«??«, .  30 

"  33.  Horizontal  section  of  skull  of  Dinoceras  laticeps, 30 

"  34.  Vertical  longitudinal  section  of  skull  of  7)Miocer«s  «nV«527e, 31 

"  35.  Vertical  transverse  section  of  skull  of  Dinoceras  mirabile, 31 


xii  DINOCERATA. 

CHAPTER    II. 

'  Page. 

Figure  36.     Lower  jaw  of  Tinoceras  annectens, j  36 

"       37.     The  same  jaw;  seen  from  above, 36 

"       38.     Tuower  ]aw  oi  Tinoceras  long icej^s,  with  n-pper  canine  in  iwsit'ion, SI 

"       39.     Lower  jaw  of  Dinoceras  ndrahile, 38 

"       40.     The  same  jaw;  seen  from  the  front, . 38 

"       4] .     Lower  jaw  of  Uintatherium.  segne, 39 

"       42.     The  sam.e  jaw;  seen  from  above, 39 


CHAPTER     III. 

FiGUEE  43.  Incisor  of  Dinoceras  mii-abile, 42 

"  44.  IncisoY  oi  Dinoceras  mirahile, 42 

"  45.  Incisor  of  Dinoceras  mirabile, _ 42 

"  46.  Upjjer  canine  of  2)i?ioceras  ^wcore, ._ .    _..  43 

'•  47.  'U-pY^x  canine,  of  Dinoceras  laticeps, .  43 

"  48.  Upper  canine  of  Tinoceras  longiceps, 43 

"  49.  Upper  canine  of  Tinoceras  grande,  _- 44 

"  50.  Upfier  canine  of  Dinoceras  laticeps, .- .- 44 

''  51.'  Upper  canine  of  Tinoceras  ingens, ._  45 

"  52.  XSy^gx  canine  oi  Tiyioceras  jnignax^ _   45 

"  53.  Upi^er  molar  series  of  Tinoceras  stenojys, .-. 47 

''  54.  Lower  molar  series  of  same  individual, 47 

"  55.  Upper  molar  series  of  6'o«/p/;of?on  Afl«2a<M«, 52 

"  56.  Lower  molar  series  of  same  individual, -    .. 52 


Figure  57. 

"  58. 

"  59. 

"  60. 

•'  61. 

"  62. 

"  63. 
64. 

"  65. 

"  66. 

"  67. 

"  68. 

"  69. 

"  70. 


CHAPTER     IV. 

Skull  of  Dinoceras'laticeps,  male, 54 

Skull  of  Dinoceras  laticeps,  female, 54 

Cast  of  brain-cavity  of  Tinoceras  ingens, 55 

The  same  cast ;  superior  view, 55 

Cast  of  brain-cavity  of  Uihtatherium  robustum,   ... 57 

The  same  cast ;   superior  view, 57 

Outline  of  skull  of  Dinoceras  mirabile,  with  brain-cast  in  position,  ._  61 

Outline  of  skull  of  Drontotherimn  ingens,  with  brain-cast  in  position,  61 

Outline  of  skull  of  horse  [Equus  caballus),  with  bi'ain-cast  in  position,  61 

Skull  of  Coryphodon  hamatus,  with  brain-cast  in  position, 63 

Skull  of  Tinoceras  pugtiax,  with  brain-cast  in  position, 63 

Skull  of  Puloeosyops  laticeps,  with  brain-cast  in  position, 63 

Skull  of  Limnoliyus  robustus,  with  brain-cast  in  position,.  _ 63 

Skull  of  Colonoceras  agrestis,  with  brain-cast  in  position, 64 


ILLUSTRATIONS. 


FiGtTEE  71.  Skull 

"  72.  Skull 

"  73.  Skull 

"  74.  Skull 

"  75.  Skull 

"  76.  Skull 

"  77.  Skull 

"  78.  Skull 

"  79.  Skull 

"  80.  Skull 

"  81.  Skull 

"  82.  Skull 

"  83.  Skull 


Page. 

of  Ilyrachyus  Bairdianus,  with  brain-cast  in  position, 64 

of  Aniynodo7i  advenits,  with  brain-cast  in  position, 64 

of  Eporeodon  socicdis,  with  brain-cast  in  position, _.  64 

of  Mastodon  America?uis,  with  brain-cast  in  position, 65 

of  Elotherium  crassum,  with  brain-cast  in  position, 65 

of  Platygonus  eompressiis,  with  brain-oast  in  position, 65 

of  Eleplias  Indicus,  with  brain-cast  in  position, _-.  66 

of  Tapirns  terrestris,  with  brain-cast  in  position, 66 

of  Rhinoceros  Sumatrensis,  with  brain-cast  in  position, 06 

of  Auchenia  vicugna,  with  brain-cast  in  position,   — 67 

of  Cermis  Virginianus,  with  brain-cast  in  position, 67 

of  Hippop)Otan\us  anqyhihius,  with  brain-cast  in  position,  _ 67 

of  Dicotyles  torquatus,  with  brain-cast  in  position,  . 67 


CHAPTER    V. 

Figure  84.  Atlas  of  Tinoceras  grande;  front  view, 71 

"       85.  The  same  vertebra;  back  view, 71 

"       86.  The  same  vertebra;  bottom  view, 71 

"       87.  Fourth  cervical  vertebra  of  27«oce?-ffls  (/raHcZe/  front  view, 75 

"       8S.  The  same  vertebra;  side  view, 75 

■'       89.  Fifth  cervical  vertebra  of  Dinoceras  mirabile;  front  view, 76 

"       90.  The  same  vertebra;  side  view, . 76 

•     "       91.  Sixth  cervical  vertebra  of  Z>?«oce?'as  »«V«5«7e/  back  view, 77 

"       92.  The  same  vertebra;  side  view, .-.. 77 

"       93.  Sixth  cervical  vertebra  of  Z>moce?-tfs  «we2rai/  front  view, 77 

"       94.  The  same  vertebra;  side  view, 77 


CHAPTER    VI. 


FiGD 


RE  95. 

96. 
97. 


100. 
101. 
102. 
103. 
104. 
105. 


First  dorsal  vertebra  of  Dinoceras  niirahile;  front  view, 80 

The  same  vertebra;  side  view, .--  80 

First  dorsal  vertebra  of  Tinoceras  anceps;  front  view, 80 

The  same  vertebra ;  side  view, . 80 

Second  dorsal  vertebra  of  Dinoceras  mirabile;  front  view, 82 

The  same  vertebra;  side  view, 82 

Third  dorsal  vertebra  of  Uintatheriiim  segne;  front  view, 83 

The  same  vertebra;  side  view, 83 

Posterior  dorsal  vertebra  of  Dinoceras  lucare;  front  view, 84 

The  same  vertebra ;  side  view, .-. . 84 

The  same  vertebra;  back  view, 84 


Xiv  DINOCERATA. 

CHAPTER     VII. 

Page. 

Figure    106.     Section  oi  huraerns  oi  Ditiocei'as  mirabile, 91 

107.  Section  oi  humerus  oi  Dinocer as  mirab He, . . 91 

108.  Section  of  radms  of  Dinoceras  mirahile, 94 

109.  Section  of  radius  of  Dinoceras  mirdbile, 94 

1 1 0.  Section  of  nlna  of  Dinoceras  lucare, 98 

111.  Section  of  ulna  of  Dinoceras  mirabile, 98 


CHAPTER    VIII. 

Figure    112.  Scaphoid  of  Z>«;ioceras  to^ice^js/  side  view, 103 

113.  Scaphoid  of  Dinoceras  mirahile;  side  view, 103 

114.  Lunar  of  Dinoceras  mirabile;  front  view, 105 

115.  Lunar  of  Tinoceras  ingens;  side  view, 105 

1 16.  The  same  bone;  distal  end, 105 

117.  Pyramidal  of  Tinoceras  ingens;  distal  end, 108 

118.  Pyramidal  of  Dinoceras  mirabile;  distal  end,  ._ 108 

119.  Trapezoid  of  Dinoceras  m  irabile;  side  view, 112 

1 20.  The  same  bone;  distal  end, 112 

121.  Magnum  of  Dinoceras  mirabile;  side  view, 115 

122.  '^la.gnuxQ.  oi  Dinoceras  mirabile;  side  view, .,. ■_  _  115 

123.  Unciform  of  Dinoceras  mirabile;  side  view, - 119 

124.  Unciform  of  Tinoceras  ingens;  side  view, 119 


CHAPTER     IX. 

FiGUEE    125.  Second  rih  of  Uintatherium  latiJ''rons;  iioatevior  Yie-w, 130 

126.  The  same  rib;  front  view, 130 

127.  The  same  rib;  inner  view, 130 

1  28.  The  same  rib ;  proximal  end, 130 

1 29.  Anterior  rib  of  Dinoceras  mirabile;  f)osterior  view, 131 

1  30.  The  same  rib;  inner  view, 131 

131.  Tlie  same  rib;  front  view, 131 

132.  The  same  rib;  proximal  end, 131 

133.  Sternum  of  Dinoceras  mirahile  ;  top  view, 134 


CHAPTER    X. 


FiGUBE    134.     Pelvis  of  Tinoceras  ingens  ;  seen  from  below, 136 

"         135.     Tlie  same  j)elvis;  front  view, 136 

"         136.     Cawiai  vertehva  oi  Di?wceras  laticeps, 138 


ILLUSTRATIONS.  SV 

CHAPTER     XI. 

Page. 

Figure    13V.     Section  oi  fexanv  oi  Dinoceras  mirabile, 141 

"         138.     Section  oi  iemiir  oi  J}i>wcet  as  mii-abile,- 141 


CHAPTER     XII. 


Figure 

139. 

" 

140. 

" 

141. 

(( 

142. 

" 

143. 

" 

144. 

" 

145. 

" 

146. 

Astragalus  of  Dlnoceras  laticeps  ;  top  view, 149 

The  same  bone  ;  bottom  view, 149 

Astragalus  of  Tinoceras  ingens  •  top  view, 149 

The  same  bone  ;  bottom  view, 149 

Calcaneum  of  Dinoceras  mirabile  ;  top  view, 152 

Calcaneum  of  Dinoceras  mirabile ;  top  view, 152 

Cuboid  of  Dinoceras  mirabile ;  side  view, -. 154 

The  same  bone  ;  proximal  end, 154 


CHAPTER     XIV. 


Figure    147.  Diagram  to  illustrate  the  genealogy  of  Ungulate  Mammals, .  173 

"  148.  Left  hind  limb  of  Baptanodon  discus, 183 

"  149.  Right  fore  foot  of  water  tortoise  {Chelydra  serpentina), 183 

"  150.  Left  fore  foot  of  Cvryphodon  hamatus, 184 

"  151.  Left  hind  foot  of  same, 184 

"  152.  Left  fore  foot  of -Z>j?ioce?'a!S  »ijV«6j7e, 184 

"  153.  Left  hind  foot  of  same, 184 

"  154.  heit  iore  foot  ot  Syrax  ca2}ensis, 185 

"  155.  Left  hind  foot  of  same, 185 

"  156.  Left  fore  foot  of  JSlephas  Indiciis, 185 

"  157.  Left  hind  foot  of  same,    185 

'"■  158.  'Leit  iore  ioot  oi.  Rhinoceros  blcornis, 186 

"  159.  Left  hind  foot  of  same, 186 

"  160.  Right  fore  foot  of  Brontotherium  ingens, . 186 

"  161.  Right  hind  foot  of  same,  -  _   186 

"  162.  "Leit  ioxe  toot  oi  JEporeodoH  socialis, 187 

"  163.  Left  hind  foot  of  same, 187 

"  164.  Left  fore  foot  of  Hippopotamus  ampjhibius, 187 

"  165.  Left  hind  foot  of  same, — .....  187 

"  166.  Left  fore  foot  of  horse  (.£'(7«M.s  ca5aZ^i(«), 188 

"  167.  Left  hind  foot  of  same, 188 

'■'  168.  Left  fore  foot  of  goat  ( Capra  hircus), 188 

"  169.  Left  hind  foot  of  same, 188 


xvi  DINOCERATA. 

"SYlSrOPSIS. 

Page. 

FiGUEE  170.  'Nasals  oi  Dinoceras  cnneum, 197 

"  171.  Skull  oi  Di7ioceras  cuneum  /  seen  from  above, 198 

"  172.  Nasals  oi  Di?iocer as  lucare, .__ 200 

"  173.  Nasals  oi  Din oceras  lucare,.. 201 

"  174.  Nasals  oi  Di?ioceras  rejfexuiii, . 201 

"  175.  Nasals  oi  Tiiwceras  anceps, 202 

"  176.  Left  parietal  protuberance  of  TYjioeeras  ance^w y  side  view, 203 

"  177.  The  same  specimen  ;  front  view, 203 

"  178.  Vertical  section  through  cranium  of  Tinoceras  affitie, 204 

"  179.  The  same  specimen  ;  seen  from  above, _. .  204 

"  180.  Skull  of  Tinoceras  cornutum ;  side  view, 206 

"  181.  The  same  skull ;  seen  from  below, 207 

"  182.  Nasals  of  Tinoceras  crassifrons, —  208 

"  183.  Nasals  oi  Tinoceras  galeatuni,  ...    -_  209 

"  184.  Posterior  surface  of  same  skull, 209 

"  185.  Nasals  oi  Tinoceras  grande, 210 

"  186.  Nasals  oi  Tinoceras  Mans, .. 210 

"  187.  Nasals  of  l^inoceras  jiigum, 212 

"  188.  Upper  molars  of  2?Mocer«s  ZacMS^re  /  seen  from  below, 212 

"  189.  Nasals  oi  Tinoceras  latum, 213 

"  190.  Nasals  oi  Tinoceras  latum, 213 

"  191.  Left  maxillary  protuberance  of  Tinoceras  longiceps j  side  view,--  214 

"  192.  Left  parietal  protuberance  of  same  skull ;  side  view, .    .    214 

"  193.  Skull  of  Tinoceras  Speirianum  ;  side  view, 216 

"  194.  Skull  and  lower  jaw  of  Tinoceras  stenops ;  side  view, ._ 217 

"  195.  Sikvill  oi  Uintatheriumrobiistum ;  hoiX,ov!i.Y\ew,  . ... 219 

"  196.  Lower  jaw  of  TJintatheriiim  fissidens ;  top  view, 220 

"  197.  The  same  specimen  ;  front  view, 220 

"  198.  Skull  of  Uintatherium  Leidianuni  ;  oblique  side  view, 221 

"  199.  Maxillary  protuberances  of  Uintatheriitm  segne ;  seen  from  above,  222 

"  200.  The  same  specimen  ;  seen  from  in  fi-ont, 222 


All  the  illustrations  in  the  present  volume  are  original,  with  the  exception  of  nine 
woodcuts,  for  which  due  credit  is  given  on  the  pages  where  they  are  used. 


PREFACE. 


The  present  Memoir  is  the  second  of  a  series  of  Monographs  designed 
to  make  known  to  science  the  Extinct  Vertebrate  Life  of  North  America. 
In  the  first  volume,  on  the  Odontornithes,  or  Birds  with  Teeth,  the  author 
gave  the  result  of  his  investigations  of  that  remarkable  group,  which  he 
discovered  in  the  Cretaceous  deposits  on  the  Eastern  slope  of  the  Rocky 
Mountains. 

This  second  Monograph  contains  the  full  record  of  a  peculiar  order  of 
Mammals,  which  the  author  also  brought  to  light  in  the  eai-ly  Tertiary 
strata  of  the  great  central  plateau  of  the  continent. 

In  preparing  the  present  volume,  it  has  been  the  aim  of  the  author  to 
do  full  justice  to  the  ample  material  at  his  command,  and,  where  possible, 
to  make  the  illustrations  tell  the  main  story  to  anatomists.  The  text  of 
such  a  Memoir  may  soon  lose  its  interest,  and  belong  to  the  past,  but 
good  figures  are  of  permanent  value  in  all  departments  of  Natui-al  Science. 
What  is  now  especially  needed  in  Palaeontology  is,  not  long  descriptions 
of  fragmentary  fossils,  but  accurate  illustrations  of  characteristic  type 
specimens.  In  the  fifty-six  lithographic  plates,  and  nearly  two  hundred 
original  woodcuts,  in  the  present  volume,  it  is  believed  that  this  requirement 
is  fairly  met ;  since  all  the  more  important  specimens  of  the  JDinocerata  now 
known  are  represented,  and  at  least  one  figm-e  is  given  of  every  species. 


xviii  DINOCEKATA. 

The  same  general  plan  will  be  followed  in  the  third  Monograph,  on 
the  Sauropoda,  whicli  comes  next  in  the  series,  and  is  now  approaching 
completion.  Ninety  lithographic  plates,  and  a  large  number  of  woodcuts, 
will  be  used  to  illustrate  it.  The  fourth  volume,  on  the  Stegosauria,  which 
follows,  will  likewise  be  very  fully  illustrated.  A  great  portion  of  the 
lithographic  plates  to  accompany  it  are  finished,  and  part  of  them  are 
already  printed.  Other  monographs  of  the  series,  now  in  preparation, 
will  appear  in  due  time. 

To  General  Sheridan  and  Greneral  Sherman  of  the  United  States 
Army,  the  author's  best  thanks  are  due  for  important  assistance  in  his 
Western  explorations,  during  which  the  discoveries  here  recorded  were 
made.  Other  officers  of  the  Army,  who  commanded  his  escort,  and  aided 
him  in  many  ways,  also  deserve  grateful  acknowledgments. 

For  direct  aid  in  collecting  the  specimens  on  which  the  present 
volume  is  based,  the  author  is  indebted  to  the  members  of  the  Yale 
College  expeditions,  which  explored  so  successfully  many  portions  of  the 
AYestern  Territories. 

The  thanks  of  the  author  are  especially  due  to  Mr.  Oscar  Harger, 
assistant  in  the  Yale  Museum,  for  valuable  aid  in  the  field,  and  in  the 
preparation  of  the  present  memoir  Messrs.  S.  W.  Williston,  G.  Baur,  and 
M.  Schlosser,  also  his  assistants,  have  likewise  aided,  especially  while  the 
volume  was  passing  through  the  press, 

Yale  College,  New  Haven,  Conn.,  December  15th,  1884. 


INTRODUCTIO]^. 


Among  the  many  extinct  animals  discovered  in  the  Tertiary  deposits 
of  the  Rocky  Mountain  region,  none,  perliaps,  are  more  remarkable  than 
the  huge  mammals  of  the  order  Dinocerata.  Their  remains  have  hitherto 
been  found  in  a  single  Eocene  lake-basin  in  Wyoming,  and  none  are 
known  from  any  other  part  of  this  country,  or  from  the  Old  World. 
These  gigantic  beasts,  which  nearly  equalled  the  elephant  in  size,  roamed 
in  great  numbers  about  the  borders  of  the  ancient  tropical  lake  in  which 
many  of  them  were  entombed. 

This  lake-basin,  now  drained  by  the  Green  River,  the  main  tributary 
of  the  Colorado,  slowly  filled  up  with  sediment,  but  remained  a  lake  so 
long  that  the  deposits  formed  in  it,  during  Eocene  time,  reached  a  vertical 
thickness  of  more  than  a  mile.  The  Wasatch  Mountains  on  the  West, 
and  the  Uinta  chain  on  the  South,  were  the  main  sou.rces  of  this  sediment, 
and  still  protect  it,  but  the  Wind  River  range  to  the  North,  and  other 
mountain  elevations,  also  sent  down  a  vast  amount  of  material  into  this 
great  fresh-water  lake,  then  more  than  one  hundred  miles  in  extent. 

At  the  present  time,  this  ancient  lake-basin,  now  six  to  eight 
thousand  feet  above  the  sea,  shows  evidence  of  a  vast  erosion,  and 
probably  more  than  one-half  of  the  deposits  once  left  in  it  have  been 
washed  away,  mainly  through  the  Colorado  River.  What  remains  forms 
one  of  the  most  picturesque  regions  in  the  whole  West,  veritable 
Mauvaises  terres,  or  bad  lands,  where  slow  denudation  has  carved  orxt 
cliffs,  peaks,  and  columns  of  the  most  fantastic  shapes,  and  varied  colors. 


2  DINOCERATA. 

This  same  action  has  brought  to  light  the  remains  of  many  extinct 
animals,  and  the  bones  of  the  Dinocerata,  from  their  great  size,  naturally 
first  attract  the  attention  of  the  explorer. 

The  first  remains  of  the  Dinocerata  discovered  were  found  by  the 
author,  in  September,  1870,  while  investigating  this  Eocene  lake-basin, 
which  had  never  before  been  explored.  Various  remains  of  this  group 
were  also  collected  by  other  members  of  the  expedition,  and  among  the 
specimens  thus  secured  was  the  type  of  Tinoceras  anceps,  described  by  the 
author  in  the  following  year,  and  now  more  fully  in  the  present  volume. 
In  the  same  geological  horizon  with  these  remains,  a  rich  and  varied 
vertebrate  fauna,  hitherto  unknown,  was  found. 

Among  the  animals  here  represented  were  ancestral  forms  of  the 
modern  horse  and  tapir,  and  also  of  the  pig.  Many  others  were  found 
related  to  the  recent  Lemurs ;  also  various  Carnivors,  Insectivors, 
Rodents,  and  small  Marsupials ;  and  of  still  more  importance,  remains 
were  hei'e  brought  to  light  of  another  new  order  of  mammals,  the 
Tillodonts,  quite  unlike  any  now  living.  Crocodiles,  tortoises,  lizards, 
serpents,  and  fishes  also  swarmed  in  and  about  the  waters  of  this  ancient 
lake,  while  around  its  borders  grew  palms,  and  other  tropical  vegetation. 

A  later  Eocene  lake-basin,  south  of  the  Uinta  Mountains,  was 
discovered,  in  October,  1870,  by  the  same  expedition,  and  named  by 
the  author  Uinta  basin.  In  the  attempt  to  explore  it,  our  party  endured 
much  hardship,  and  also  were  exposed  to  serious  danger,  since  we  had 
only  a  small  escort  of  United  States  soldiers,  and  the  region  visited  was 
one  of  the  favorite  resorts  of  the  Uinta  Utes.  These  Indians  were  then, 
many  of  them,  insolent  and  aggressive,  and  since  have  been  openly 
hostile,  at  one  time  massacring  a  large  body  of  government  troops  sent 
against  them.  Two  subsequent  attempts  by  the  author  to  explore  this 
basin  met  with  little  success.  This  lower  lake  was  of  upper  Eocene  age, 
and  its  extinct  fauna  appears  to  correspond  more  nearly  to  that  of  the 
Paris  basin  than  any  other  yet  discovered  in  this  countrj^.^ 

'  Some  results  of  this  Expedition  may  be  found  in  an  article  by  the  author  on  the 
"  Geology  of  the  Eastern  Uintah  Mountains,"  American  Journal  of  Science  and  Arts, 
vol.  i,  p.  191,  March,  1871. 


INTRODUCTION.  3 

The  remarkable  Eocene  basin  North  of  the  Uinta  Mountains,  where 
alone  the  Dinocerata  had  been  found,  offered  so  inviting  a  field  for 
exploration,  that  in  the  spring  of  the  following  year,  1871,  the  author 
began  its  systematic  investigation.  An  expedition  was  again  organized, 
with  an  escort  of  United  States  soldiers,  and  the  work  continued  during 
the  entire  season.  Among  the  very  large  collections  thus  secured,  were 
numerous  specimens  of  the  Dinocerata,  Avhich  furnished  important 
characters  of  the  group. 


Map  showing  region  of  Dinoceeas  beds. 


In  the  succeeding  spring,  1872,  the  explorations  in  this  region  were 
continued,  and  soon  resulted  in  the  discovery  of  the  tyjje  sjiecimen, 
including  the  skull  and  a  large  portion  of  the  skeleton,  of  Dinoceras 
mirabile,   and  on  this  new  genus  the  author  based  the   order  Dinocerata 


4  DINOCEIIATA. 

Other  important  specimens,  obtained  at  tliis  time,  and  described  by  the 
author,  were  the  t3qDes  of  Diiioceras  liicare,  Tinoceras  grande,  Tinoceras 
laciistre,  and  others  of  scarcely  less  interest. 

In  the  following  season,  1873,  the  author  organized  another  large 
expedition,  with  government  escort,  and  made  a  very  careful  examination 
of  the  regions  in  this  same  basin  that  remained  unexplored.  One  of  the 
specimens  of  special  importance  thus  secured  was  the  type  of  Dinoceras 
laticeps,  with  the  skull  and  lower  jaw  nearly  complete.  Many  other 
individuals  of  the  Dinocerata  were  also  discovered,  and  the  abundant 
material  then  collected  was  sufficient  to  clear  up  most  of  the  doubtful 
points  in  this  group. 

The  research  was  continued  systematically  during  the  next  season, 
also,  1874,  and  again  in  1875,  with  good  results.  Since  then,  various 
small  parties,  at  different  times,  have  been  equipped  and  sent  out  by  the 
author  to  collect  in  this  basin ;  and,  finally,  during  the  entire  season  of 
1882,  the  work  was  vigorously  prosecuted  under  the  direction  of  the 
author,  and,  from  July  of  that  year,  under  the  avispices  of  the  United 
States  Geological  Survey. 

The  specimens  thus  brought  together  by  all  these  various  expeditions 
and  parties  are  now  in  the  museum  at  Yale  College,  and  represent  more 
than  two  hundred  individuals  of  the  Dinocerata  alone.  Of  these,  not  less 
than  seventy-five  have  portions  of  tlie  skull  more  or  less  perfectly 
preserved,  and  in  more  than  twenty  it  is  in  good  condition.  The  present 
volume  is  based  on  this  material,  amply  sufficient,  it  is  believed,  to 
illustrate  all  the  more  important  parts  of  the  structure  of  this  remarkable 
group. 

The  remaining  material  of  the  Dinocerata,  now  known,  consists  of  a 
few  specimens  collected  by  Dr.  Leidy  in  1872,  including  the  type  of  the 
genus  TJintatlierium ;  various  remains  secured  in  the  same  year  by  Prof. 
Cope,  to  which  he  applied  the  names  Loxolophodon  and  Eohasileiis,  with 
a  later  acquisition,  called  Bathyopsis ;   and  a  number  of  specimens  more 


INTRODUCTION.  5 

recently  obtained  by  parties  from  Princeton  College.  Although  these 
remains  show  few,  if  any,  characters  of  the  JDinocerata  not  better 
represented  in  the  larger  collection  of  the  Yale  Museum,  full  references 
to  the  more  important  specimens,  in  most  cases  with  illustrations,  are 
given  in  the  present  memoir,  especially  in  the  Synopsis  at  the  end 
of  the  volume. 

The  Dinocerata  have  hitherto  been  found  in  a  well  marked  geological 
horizon  of  the  middle  Eocene.  The  relations  of  this  horizon  to  other 
deposits  of  Tertiary  age  are  important,  and  cannot  readily  be  understood 
without  having  in  mind  the  principal  changes  that  took  place  in  the 
geology  of  the  Rocky  Mountain  region  during  this  period.  These 
changes  and  their  results  may  be  briefly  stated  as  follows : 

The  Tertiary  of  Western  America  comprises  the  most  extensive 
series  of  deposits  of  this  age  known  to  geologists,  a^nd  important  breaks 
in  both  the  rocks  and  the  fossils  separate  it  into  three  well-marked 
divisions.  These  natural  divisions  are  not  the  exact  equivalents  of  the 
Eocene,  Miocene,  and  Pliocene  of  Europe,  although  usually  so  considered, 
and  known  by  the  same  names  ;  but,  in  general,  the  fauna  of  each  appears 
to  be  older  than  that  of  its  corresponding  representative  in  the  other 
hemisphere ;  an  important  fact,  but  little  recognized.  This  partial 
resemblance  of  our  extinct  faunas  to  others  in  regions  widely  separated, 
where  the  formations  ai'e  doubtless  somewhat  different  in  geological  age,  is 
precisely  what  we  might  expect,  if,  as  was  probable,  the  main  migrations 
took  place  from  this  continent.  It  is  better  at  once  to  recognize  this 
general  principle,  rather  than  attempt  to  bring  into  exact  parallelism 
formations  that  were  not  contemporaneous. 

The  fresh-water  Eocene  deposits  of  our  Western  Territories,  which 
are  in  the  same  region  at  least  two  miles  in  vertical  thickness,  may  be 
separated  into  three  distinct  subdivisions.  The  lowest  of  these,  resting 
unconformably  on  the  Cretaceous,  has  been  termed  the  Vermilion  Creek, 
or  Wasatch,   group.      It  contains   a  well-marked  mammalian  fauna,  the 


6  MNOCERATA. 

largest  and  most  characteristic  genus  of  which  is  the  ungulate  Coryphodon, 
and  hence  the  author  has  called  these  deposits  the  Coryphodon  beds.  The 
middle  Eocene  strata,  which  have  been  termed  the  Green  Eiver  and 
Bridger  series,  has  been  designated  by  the  author  the  Dinoceras  beds,  as 
the  gigantic  animals  of  this  order  are  only  found  here.  It  is,  however, 
better  to  separate  the  Green  River  series,  under  the  term  Heliobatis  beds, 
and  this  is  done  in  the  present  volume.  The  name  Dinoceras  beds  will  then 
apply  to  the  Bridger  series  alone.  The  uppermost  Eocene,  or  tlie  Uinta 
group,  is  especially  well  characterized  by  large  mammals  of  the  genus 
Diplacodon,  and  hence  termed  by  the  author  Diplacodon  beds.  The  fauna 
of  each  of  these  three  subdivisions  was  essentially  distinct,  and  the  fossil 
remains  of  each  were  entombed  in  different  and  successive  ancient  lakes. 

It  is  important  to  remember  that  these  Eocene  lake-basins  all  lie 
between  the  Hocky  Mountains  on  the  east  and  the  Wasatch  Range  on 
the  west,  or  along  the  high  central  plateau  of  the  continent.  As  these 
mountain  chains  were  elevated,  the  inclosed  Cretaceous  sea,  cut  off  from 
the  ocean,  gradually  freshened,  and  formed  these  extensive  lakes,  while 
the  surrounding  land  was  covered  with  a  luxuriant  tropical  vegetation, 
and  with  many  strange  forms  of  animal  life.  As  the  upward  movement 
of  this  region  continued,  these  lake-basins,  which  for  ages  had  been  filling 
up,  preserving  in  their  sediments  a  faithful  record  of  Eocene  life-history, 
were  slowly  drained  by  the  constant  deepening  of  the  outflowing  rivers, 
and  they  have  since  remained  essentially  dry  land. 

The  Miocene  lake-basins  are  on  the  flanks  of  this  region,  where  only 
land  had  been  since  the  close  of  the  Cretaceous.  These  basins  contain 
three  faunas,  nearly  or  quite  distinct.  The  lowest  Miocene,  which  is 
found  east  of  the  Rocky  Mou.ntains,  alone  contains  the  peculiar  mammals 
known  as  the  Brontotheridce,  and  these  deposits  have  been  called  by  the 
author  the  Brontotherium  beds.  The  strata  next  above,  which  represent 
the  middle  Miocene,  have  as  their  most  characteristic  fossil  the  genus 
Oreodon,  and  are  known  as  the  Oreodon  beds.  The  upper  Miocene,  which 
occurs  in  Oregon,  is  of  great  thickness,  and  from  one  of  its  most  important 
fossils,  Mioliippus,  has  been  designated  as  the  Miohippus  series.  The 
climate  here  during  this  period  was  warm  temperate. 


INTRODUCTION. 


i&teSS^M 


Tapir,  feccary,  uiauu,  Llama. 

Bos,  Equus,  Megatherium,  3fylodon. 


Equue,  Tapirus  Elephas. 

\  PUoMpp-us,  Tapiravus,  Mastodon,  Protohippus,  Procamelus, 

I    Aceratherium,  Bos,  Morotherium. ^^^ 


Mioliippus  Beds. 
Oreodon  Beds. 
BronlotheriumBeds 


Diplacodoii  Beds. 
Diuooeras  Beds. 

Green  River,  or 

Heliobatis,  Beds, 
Coryphodon  Beds. 


Laramie  Series,  or 
Hadrosaurus  Beds. 
Fo.x  Hill  group. 


Colorado  Series,  or 
PteranodoD  Beds. 


Dakota  Group. 


Atlantosaurus  Beds 
Baptanodon  Beds 


Otozoiim,  or 
CoDn.  River,  Beds. 


MioJdppus,  Diceratherium,  Thinohyus. 


Oreodon,    Eporeodon, 
{Moropus). 
Brontolherium,  Menodus, 


.,  Hyracodon.    EclentateB 
Eloiherium. 


Diplacodon,  Epihippus,  Amynodnn. 

miocera^,    Tinoceras,    Uintatherium,    Limnohyxis,  PaUso- 
syops,  Orohippus,  Helatetes,  Hyrachyus,  Colonoceras. 

Heliobatis,  Amia,  Lepidosteus. 


Hadrosaurus,  Dryptosaurus  (Loelapa). 


Pterodactyls  {Pteranodon),   Pleslosfturti. 


Dinosaurs,  Atlautosaurus,  Brontosaurus,  Morosaurus.  Diplo 
docus,  Stegosaurus,  Catnptonotus,  AUosaurus.  Turtles 
Crocodiles.  Mauiuials  {Dryolestes,  Stylaeodon,  Tinodon 
Ctenacodoii) .  Bird  iZaopteryxi.  Baptanodon  iSauranodon) 


First  Manimals  ( Dromatheriuni) . 

Dsaur  Foot-prints,  Amphiaaurus,    Crocodiles  {Belodon). 


Nothodon  Beds. 


Reptiles  iNothodon,  Sphenacodon) . 


Carboniferous 


Coal  Measures,  or 
Eosaurus  Beds. 


Subcarboniferous. 
or  Sauropus  Beds. 


First  Reptiles  (?)  Eosaurus. 


First  tnown  Amphiliians  (Labyrinthodonts),  Sauropus. 


Dinichthys  Beds. 
Schoharie  Grit. 


Dinichthys. 

First  known  Fishes. 


Upper  Silurian. 


Lower  Silurian. 


No  Vertebrates  known. 


Section  to  illustrate  Vertebrate  Life  in  America. 


8  DINOCERATA. 

Above  the  Miocene,  east  of  the  Rockj^  Mountains,  and  on  the  Pacific 
coast,  the  Phocene  is  well  developed,  and  is  rich  in  vertebrate  remains. 
The  strata  rest  unconformably  on  the  Miocene,  and  there  is  a  well-marked 
faunal  change  at  this  point,  modern  types  now  first  making  their 
appearance.  For  these  reasons,  Ave  are  justified  in  separating  the  Miocene 
from  the  Pliocene  at  this  break ;  although  in  Eurojje,  where  no  great 
break  exists,  the  line  seems  to  have  been  drawn  at  a  somewhat  higher 
horizon.  Our  Pliocene  forms  esseutially  a  continuous  series,  although  the 
upper  beds  may  be  disting'uished  from  the  lower  by  the  presence  of  a 
true  Etpms,  and  some  other  existing  genera.  The  Pliocene  climate  was 
similar  to  that  of  the  Miocene.  The  Post-Pliocene  beds  contain  many 
extinct  mammals,  and  may  thus  be  separated  from  recent  deposits.  ^ 

With  this  introduction,  the  table  of  strata  on  page  7  will  make  clear 
the  general  position  of  the  g-eological  horizon  in  which  the  Dinocerata  are 
found,  and  especially  its  relation  to  other  deposits  of  Tertiary  age.  To 
make  the  subject  clearer  to  the  general  reader,  the  section  is  enlarged  to 
include  the  whole  geological  series.  The  names  applied  to  the  different 
horizons,  some  used  here  for  the  first  time,  are,  in  general,  those  of  the 
most  important  vertebrates  found  in  each,  and  the  section  thus  becomes  a 
condensed  index  of  vertebrate  life  in  America. 

The  localities  in  which  the  Dinocerata  have  been  found  are  on  both 
sides  of  the  Green  River,  and  mainly  south  of  the  Union  Pacific  Railroad, 
in  Wyoming.  Of  two  hundred  individuals  in  the  Yale  Museum,  about 
equal  numbers  were  found  east  and  west  of  this  River,  the  distance 
between  the  extreme  localities  in  this  direction  being  more  than  one 
hundred  miles.  The  map  on  page  3  covers  this  region,  and  the  more 
important  localities  referred  to  in  the  volume  are  there  indicated. 

'  For  a  more  complete  presentation  of  this  subject,  see  the  author's  address  on 
the  Introduction  and  Succession  of  Vertebrate  Life  in  America,  delivered  before  the 
American  Association  for  the  Advancement  of  Science,  at  Nashville,  Tenu.,  Aug.,  1877. 


INTRODUCTION.  9 

The  remains  of  the  JDinocerata  are  imbedded  usually  in  indurated 
clays,  gray  or  green  in  color,  but  sometimes  they  are  found  in  hard 
sandstone.  The  series  of  strata  enclosing  them  are  at  least  five  hundred 
feet  in  thickness  in  the  same  region,  and  all  taken  together  are  probably 
one  thousand  feet. 

Among  the  fossils  found  associated  with  the  Binocerata  are  Limnohyus 
and  PalcBOsyops,  two  genera  of  perissodactyl  ungulates.  They  were 
somewhat  larger  than  a  Tapir,  and  in  these  strata  are  next  in  size  to  the 
Binocerata.  One  or  the  other  of  these  genera  occurs  wherever  the 
Binocerata  have  yet  been  found,  but  the  remains  extend  through  a  greater 
thickness  of  strata  than  those  of  the  former  group.  Another  genus  of 
ungulates  in  this  horizon  is  OroJiippus,  a  four-toed  ancestor  of  the  horse. 
Other  prominent  genera  are  Cohnoceras,  Helaletes,  and  Hyracliyus,  related 
distantly  to  the  Tapir  and  Rhinoceros. 

Two  genera,  TillotJierium  and  Stylinodon,  also  found  here,  represent  a 
remarkable  order,  named  by  the  author,  Tillodontia.  They  were  nearly 
as  large  as  a  Tapir,  and  possessed  characters  resembhng  the  Ungulates, 
the  Carnivors,  and  the  Rodents. 

Among  the  Carnivors,  the  most  formidable  was  Limnofelis,  nearly  as 
large  as  a  lion,  Oreocyon,  of  almost  equal  size,  Bromocyon,  somewhat 
smaller,  and  Limnocyon,  about  as  large  as  a  fox.  Among  the  Lemuroid 
forms  were  Hyopsodus  and  Lemuravus,  forming  the  family  LenmravidcB, 
and  having  some  affinities  with  the  South  American  Marmosets. 

In  addition  to  these,  there  were  Marsupials,  Insectivors,  Chiroptera, 
and  many  Rodents,  but  apparently  no  ti-ue  Quadrumana,  or  Edentates. 

Besides  these  Mammals,  there  were  numerous  Reptiles,  especially 
crocodiles,  turtles,  Hzards,  and  serpents,  in  great  numbers.  Fishes  were 
also  abundant,  especially  the  genera  Amia  and  Lepidosteus. 

The  Binocerata  form  a  well  marked  order  in  the  great  group  of 
Ungulata.  In  some  of  their  characters,  they  resemble  the  Artiodactyls 
(  Paraxonia);  in  others,  they  are  like  the  Perissodactyls  (Mesaxonia);  and 

2 


10  -  INTRODUCTION. 

in  others  still,  they  agree  with  the  Proboscidians.  The  points  of  similarity, 
however,  are  in  most  cases  general  characters,  which  point  back  to  an 
earlier,  primitive,  ungiilate,  rather  than  indicate  a  near  affinity  with 
existing  forms  of  these  groups.  This  subject  will  be  more  fully  discussed 
in  the  concluding  chapters  of  the  present  memoir. 

The  Dinocerata,  so  far  as  now  definitely  known,  may  be  placed  in 
three  genera,  Dinoceras,  Marsh,  Tinoceras,  Marsh,  and  Uintatherium,  Leidy. 
The  type  specimen  of  Uintatherium  was  discovered  near  the  base  of  the 
series  of  strata  containing  the  remains  of  the  Dinocerata.  Dinoceras,  so 
far  as  known,  occurs  only  at  a  higher  horizon,  while  Tinoceras  has  Ijeen 
found  at  the  highest  level  of  all.  The  characters  of  these  three  genera 
correspond  in  general  with  their  geological  position.  Uintatherium 
appears  to  be  the  most  primitive  type,  and  Tinoceras  the  most  specialized, 
Dinoceras  being  an  intermediate  form.  The  material  at  hand  for 
determining  the  characters  of  the  two  latter  forms  is  abundant,  but  in 
regard  to  Uintatherium,  some  important  points  relating  both  to  the  skull 
and  skeleton  still  remain  in  doubt. 

The  number  of  species  of  the  known  Dinocerata  is  a  difficult  matter  to 
determine,  especially  as  the  limitations  between  species  are  now  generally 
regarded  as  uncertain.  About  thirty  forms,  more  or  less  distinct,  are 
recognized  in  the  Synopsis  at  the  end  of  the  volume.  The  number  might 
easily  be  increased,  if  fragmentary  specimens  were  used  as  the  basis  for 
specific  names. 


DINOCERATA. 


CHAPTER    I. 


THE   SKULL. 

(Plates  I-XIX,  LV,  and  LVL) 
The  skull  of  Dinoceras  mirabile,  the  type  of  the  gemis  Binoceras,  on 
which  the  order  Binocerata  was  based,  is,  fortunately,  the  most  perfect  in 
preservation  of  any  yet  discovered  in  this  group.  It  has  in  addition  the 
great  advantage  for  study  of  having  belonged  to  an  animal  fully  adult,  but 
not  so  old  as  to  have  the  more  important  sutures  of  the  skull  obliterated. 
It  was,  moreover,  imbedded  in  so  soft  a  matrix  that  the  brain-cavity  and 
the  foramina  leading  from  it  could  be  worked  out  without  difficulty. 

In  removing  the  skull  from  the  rock,  on  the  high  and  almost 
inaccessible  cliff  where  it  was  found,  two  or  three  important  fragments 
were  lost,  but  the  author  subsequently  made  a  systematic  and  laborious 
search,  and  recovered  them  from  the  bottom  of  a  deep  ravine  where  they 
had  been  washed  down  and  covered  up. 

■  In  its  present  nearly  perfect  condition,  this  skull  is  well  adapted  to 
show  the  typical  characters  of  this  part,  both  in  the  genus  it  represents, 
and  in  the  order  Binocerata,  and  it  will  be  largely  used  for  this  purpose  in 
the  following  pages.  The  fact  that  a  considerable  portion  of  the  skeleton, 
also,  was  found  with  this  skull  makes  the  individual  especially  worthy  to 
be  a  type. 


12  DINOCERATA. 

The  number  of  this  specimen,  in  the  Catalogue  of  the  Yale  Museum, 
is  1036,  and  in  the  following  pages  this  number  will  be  used  to  distinguish 
this  type  from  other  individuals  of  the  same  species.  Other  important 
specimens  will  likewise  be  designated  by  their  catalogue  numbers. 

The  skull  of  Dinoceras  mirabile  is  long  and  narrow,  the  facial  portion 
being  greatly  produced.  The  basal  line,  extending  from  the  end  of  the 
premaxillaries  along  tlie  palate  to  the  lower  margin  of  the  foramen 
magnum,  is  nearly  straight.  The  top  of  the  skull  supports  three,  separate, 
transverse  pairs  of  osseous  elevations,  or  horn-cores,  which  form  its  most 
conspicuous  feature,  and  suggested  the  name  of  the  genus.  The  smallest 
of  these  protuberances  are  situated  near  the  extremity  of  the  nasals ;  two 
others,  much  larger,  arise  from  the  maxillaries,  in  front  of  the  orbits  ;  while 
the  largest  are  mainly  on  the  parietals,  and  are  supported  by  an  enormous 
crest,  which  extends  from  near  the  orbits  entirely  around  the  lateral  and 
posterior  margins  of  the  true  cranium.  These  general  chai-acters  are  well 
shown  in  Plate  I,  which  represents  the  skull  of  the  type  specimen. 

There  are  no  upper  incisors,  but  the  canines  in  the  male  are 
enormously  developed,  forming  sharp,  trenchant,  decurved  tusks,  which 
were  each  protected  by  a  dependent  process  an  the  lower  jaws.  The 
premolar  and  molar  teeth  are  very  small. 

The  orbit  is  large,  and  confluent  with  the  temporal  fossa.  The  latter 
is  of  great  extent  posteriorly,  but  the  zygomatic  arches  are  only 
moderately  expanded.  There  is  no  post-orbital  process,  but  in  Dinoceras 
mirabile,  and  in  some  other  species,  there  is  a  prominence  on  the  frontal 
bone,  directly  over  the  orbit. 

The  Nasal  Bones. 

The  nasal  bones  are  greatly  elongated,  being  nearly  half  the  length 
of  the  entire  skull.  They  project  forward  over  the  anterior  nares,  and 
overhang  the  premaxillaries.  Tliey  are  thick  and  massive  bones, 
especially  in  front,  and  are  united  together  by  a  nearly  straight  suture. 


THE  SKULL. 


13 


In  specimens  not  fully  adult,  this  suture  remains  an  open  fissure,  and  even 
in  some  adults  it  is  not  closed,  especially  in  the  anterior  part. 

The  osseous  prominences  on  the  extremity  of  the  nasal  bones  are 
their  most  marked  feature.  These  vary  much  in  form  and  size  in  the 
different  genera  of  the  group,  and  appear  to  be  characteristic  of  the  species. 


PieuKE  3. — "Sasals  of  Oinoceras  mirab  If  Miisli  (N      10  ()     t^\e  <5pecimen. 
Figure  4. — T<S asa\s  oi  Dinoceras  distan    Marsh  (\o   1001)    3   ui    male. 
Fjguke  5. — Nasals  of  Tinoceras  pugnax,  Marsh  (No.  1 044). 
FiGUKE  6. — Nasals  of  Tinoceras  annectens,  Marsh  (Xo.  1043). 
a.  side  view ;  6.  top  view ;  c.  front  view. 

All  the  figures  are  one-fifth  natural  size. 


14  DINOCERATA. 

In  Dinoceras,  they  are  small  and  sessile,  and  are  directed  upward,  and 
somewhat  outward ;  in  Tinoceras  they  are  larger,  in  most  specimens,  and 
project  more  horizontally,  visually  not  beyond  the  apex  of  the  nasals.  Some 
of  the  characteristic  forms  of  these  nasals  are  given  above,  figures  3-6, 
page  13,  and  others  will  be  found  under  the  different  species  in  the 
Synopsis  at  the  end  of  the  volume. 

On  their  lateral  margins,  the  nasal  bones  unite  by  suture  with  the 
superior  branch  of  the  premaxillary,  and,  behind  this,  with  the  maxillaries 
up  to  the  point  where  they  join  the  frontals.  These  lateral  sutures 
disappear  in  old  animals,  but  are  shown  in  the  skull  of  Dinoceras 
mirabile,  figured  in  Plate  IV.  Between  the  osseous  protuberances,  or  horn- 
cores,  of  the  maxillaries,  the  nasals  thicken  into  a  transverse  ridge,  which 
greatly  strengthens  the  skull  in  this  region.  The  development  of  this 
ridge  varies  in  different  species.  The  suture  between  the  nasals  and 
maxillaries  thus  appears  to  rise  on  the  inner  face  of  each  maxillary 
prominence,  but  the  nasals  do  not  form  any  essential  part  of  these 
elevations.  From  this  transverse  ridge,  the  nasals  expand  posteiiorly,  and 
meet  the  frontals  by  oblique  sutures,  converging  behind  to  the  median  line. 
At  the  luiion  with  the  frontals,  the  nasal  bones  are  comparatively  thin. 

On  their  under  surface,  the  nasal  bones  are  each  excavated  by  a 
broad  deep  groove,  which  is  separated  from  its  fellow  by  a  sharp  median 
ridge.  These  grooves  extend  from  the  anterior  nasal  opening  back  to  the 
frontal  bones,  and  then  expand  into  large  cavities  immediately  in  front  of 
the  olfactory  lobes  of  the  brain.  These  olfactory  chambers  differ  in  form 
and  size  in  different  species.  This  part  of  the  skull  is  shown  in  the 
sections  represented  in  figures  30-33,  pages  29  and  30. 

Pre-Nasal  Bones. 

The  anterior  extremity  of  the  nasal  bones,  in  both  Dinoceras  and 
Tinoceras,  is  formed  of  an  osseous  projection,  pointing  forward  and 
downward,  and  situated  in  front  of  and  below  the  nasal  protuberances. 
Several  specimens  in  the  Yale  Museum  show  that  this  projection  is  formed 


THE   SKULL. 


15 


of  two  separate  ossifications,  each  in  front  of  its  respective  nasal  bone. 
In  figure  5,  page  13,  they  are  shown  in  position,  with  the  sutures  uniting 
them  to  the  nasals,  and  to  each  other.  These  bones  ai-e  a  peculiar 
featvire  in  the  skull  of  Dinocerata,  and  may  be  called  the  pre-nasal  bones. 
In  very  young  animals,  they  are  unossified;  in  adult  animals,  they  are 
distinct,  as  in  the  specimen  figured;  but  in  very  old  animals  they 
become   co-ossified  with  the   nasals,   and  with   each   other. 

Fig.  7. 


riGURB  t. — Skull  of  Dinnceras  mirabile,  Marsh  (No.  1036);  with  brain-cast  in  natural  position;  seen  from  above. 
Figure  8. — The  same  view  of  a  young  specimen  ol  Dinoceras  distans,  Marsli  (So.  1601). 

/■.  frontal  bone ;  m.  maxillary  bone;  m'.  maxillary  protuberance  ;  b.  nasal  bone;  n'.  nasal  protuberance; 

p.  parietal  bone ;  p'.  parielal  protuberance ;  pm.  premaxillary  bone ;  s.  supra-occipital  crest. 
Both  figures  are  one-eighth  natural  size. 

When  separate,  they  are  subquadrate  in  form,  flattened  on  the  median 
line  where  they  meet  each  other ;  and  rugose  posteriorly,  for  sutural  union 
with  the  nasals.  These  pre-nasal  bones  appear  to  be  homologous  Avith 
the  ossicle  sometimes  found  at  the  ■  extremity  of  the  snout  in  suillines, 
especially  in  the  genus  Sus. 


16 


DINOCERATA. 


Frontal  Bones. 

The  frontal  bones  in  Dinoceras  mirahile  are  shorter  than  the  nasals. 

In  all  of  the  known  skulls  of  the  Dinocerata,  the  median  suture  uniting  the 

two  frontals  is  entirely  obliterated.     The  sutures  joining   them  with  the 

nasals  in  front,  and  with  the  maxillaries  on  the  side,  is  distinct  in  the  type 

Ik,    1 


Figure  9. — Skull  of  rmoeeras  jn(/e««.  Marsh  (No.  10+1);  with  train-east  in  position ;  seen  from  above. 
Figure  10. — Same  view  of  skull  of  Dinoceras  distans,  Marsh  (No.  1235). 

/.  frontal  bone;   m.  maxillary  bone;   m'.  maxillary  protuberance;   n.  nasal  bone;  n'.  nasal  protuberance; 

jj.  parietal  bone ;  p'.  parietal  protuberance;  J)7«.  premaxillary  bone ;  s.  supraoccipital  crest. 
Both  figures  are  one-eighth  natural  size. 

of  Dinoceras  mirahile,  as  shown  in  Plates  II  and  IV.  In  this  specimen, 
there  apj^eared  to  be  indications  of  a  suture  uniting  the  frontals  with  the 
parietals,  which  indicated  that  the  former  bones  were  very  short,  and  the 
latter  very  long.  Tlie  fortunate  discovery,  however,  of  a  A^ery  young 
individual  of  this  genus  has  cleared  up  this  point  beyond  doubt. 


THE   SKULL. 


IT 


Tn  this  young  specimen,  the  fi'onto-parietal  suture  is  still  open,  and 
passes  in  a  nearly  straight  line  across  the  top  of  the  cranium  just  in  front 
of  the  summit  of  the  cerebral  hemispheres.  It  also  divides  the  posterior 
elevations,  or  horn-cores,  so  as  to  leave  the  anterior  part  of  them  on  the 
frontals,  and  the  posterior  and  highest  portion  on  the  parietals.  In  all  the 
other  known  specimens,  this  suture  is  nearly  or  quite  obliterated,  but 
distinct  traces  of  it  are  seen  in  several  crania  in  the  Yale  Museum. 

Frc.  1  L  Fig.  12. 


Figure  ]  1.  — 6kuU  of  Uiutai.ttnain  latifivns,  Marsh  (No.  1231);  seen  from  aljove. 

Figure  12. — Same  view  of  skull  of  Tinoceras  vagans,  Marsh  (ISTo.  1241). 

/.  frontal  bone;   m.  mamillary  bone;  m'.  maxillary  protuberance;  7i.  nas  1  bi^ne;  »'.  nasal  protuberance 
p.  parietal  bone;  p'.  parietal  protuberance ;  pm.  premaxillary  bone;  s.  supraoccipital  crest. 
Both  figures  are  one-eighth  natural  sue. 

The  position  of  this  suture,  and  also  that  uniting  the  frontals  with  the 
nasals,  and  the  latter  with  their  adjoining  bones,  is  well  shown  in  figure  8, 
page  15,  which  represents  the  young  specimen  (number  1601)  above 
referred  to. 

In  Dinoceras  mirabile  (number  1036),  the  frontals  are  comparatively 
thin  in  front  where  they  join  the  nasals.  Over  the  orbits,  they  become 
3 


18  DINOCERATA. 

thicker,  and  swell  into  a  distinct  prominence,  which  afforded  protection  to 
the  eye  below.  From  this  point  back  to  the  posterior  protuberances,  or 
horn-cores,  the  lateral  margin  of  the  frontal  is  thickened  into  a  strong 
crest,  which  rises  nearly  to  the  summit  of  the  elevations,  leaving  a  distinct 
notch  where  they  terminate.  This  depression  marks  the  position  of  the 
fronto-parietal  suture,  here  entirely  obliterated. 

On  the  side  of  the  cranium,  the  frontal  bones  are  bounded  anteriorly 
by  the  maxillary  above,  and,  lower  down,  by  the  lachrymal,  as  shown  in 
Plate  II.  Further  back  on  the  top  of  the  skull,  the  frontals  are  depressed, 
forming  a  deep  concavity,  the  lowest  portion  of  which  is  usually  in  front  of 
the  brain-case.  In  the  posterior  portion  of  the  frontals,  there  are  numerous 
air  cells,  which  materially  lighten  these  bones  in  this  part  of  the  cranium. 


The  Parietal  Bones. 

In  all  of  the  crania  of  the  Dinocerata  examined,  the  parietal  bones  are 
firmly  united  to  each  other  on  the  medial  line,  and  with  the  supra-occipital 
behind.  In  the  single  young  specimen  already  mentioned  (number 
1601),  the  anterior  border  of  these  bones  is  distinctly  marked  by  sutures, 
as  shown  in  figure  8,  page  15.  The  large  posterior  protuberances,  or 
horn-cores,  are  thus  mainly  on  the  parietal  bones,  and  the  lateral  crest, 
behind  these  elevations,  appears  to  be  also  composed  of  the  parietals. 
These  bones  are  thick  and  massive,  especially  over  the  brain-case,  but  like 
the  frontals  are  lightened  somewhat  by  air  cavities,  as  shown  in  figure  35, 
page  31.  Between  the  osseous  elevations,  or  horn-cores,  on  the  parietals, 
there  is  a  distinct  transverse  ridge,  which  strengthens  this  part  of  the 
cranium,  and  partially  divides  into  two  portions  the  deep  concavity 
enclosed  by  the  lateral  and  posterior  crests.  On  the  sides  of  the  cranium, 
the  parietals  form  the  upper  portion  of  the  large  temporal  fossae.  The 
suture  between  the  parietal  and  squamosal  below  may  often  be  distinctly 
made  out,  as  shown  in  Plate  II.  The  share  of  the  parietals  in  the  lofty 
occipital  crest,  cannot,  at  present,  be  determined  with  certainty,  as  here, 
even  in  the  youngest  specimens  known,  the  sutures  are  obliterated. 


THE  SKULL. 


19 


The  Occiput. 

The  occipital  region  in  all  the  known  Binocerata  is  large,  elevated, 
and  subquadrate  in  outline.  It  varies  much  in  shape  and  size  in  the 
different  genera  and  species,  and  several  of  the  principal  forms  are 
represented  below  in  figures  13-18. 

Fig.  13.  Fig.  U.  Pig.  15. 


t^^i. 


Figure  13. — Posterior  surface  of  skull  of  Dinoceras  mirahile,  Marsh  (No.  lOSfi). 
Figure  14. — Posterior  surface  of  skull  of  Dinoceras  latkeps,  Marsh  (No.  1039),  male. 
Figure  15. — Posterior  surface  of  skull  of  Dinoceras  agresie,  Marsh  (No.  1221). 
Figure  16. — Posterior  surface  of  skull  of  Tinoceras  afflne,  Marsh  (No.  1574) 
Figure  IT. — Posterior  surface  of  skull  of  Ti:o~.eras  ingens,  Marsh  (No.  1041). 
Figure  1 8. — Posterior  surface  of  skull  of  Tinoceras  pugnax,  Marsh  (No.  1 044). 

c.  occipital  condyle;   /.  foramen  magnum;   I.  lateral  crest;   o.  occipital  crest;  p.  post-tympanic  process; 

l.  crest  behind  temporal  fossa. 

All  the  figures  are  one-eighth  natural  size. 

In  Dinoceras  mirabile  (number  1036),  the  occiput  is  remarkably 
rectangular  in  outline,  as  shown  above  in  figure  13.  Its  general 
surface   is   concave,    for   the   attachment    of   the    powerful   muscles   and 


20  DINOCERATA. 

ligaments  which  supported  the  head.  The  lofty  occipital  crest  extends 
upward  and  backward,  overhanging-  the  occipital  condyles,  when  the 
skull  is  in  a  horizontal  position.  The  posterior  margin  of  the  large 
temporal  fossa  also  extends  well  backward,  forming  the  side  of  the 
occipital  concavity,  which  is  partially  divided  into  two  equal  portions  by 
a  median  vertical  ridge.  In  some  species,  this  ridge  is  very  distinct,  but, 
in  others,  it  is  almost  entirely  wanting. 

The  occipital  condyles  are  large,  and  bounded  externally  in  front 
and  below  by  a  deep  groove.  They  project  downward  and  backward, 
showing  that  the  head  Avas  declined  when  in  its  natural  position. 

In  Dinoceras  laticeps  (number  1039),  the  occiput  is  less  elevated,  and 
more  expanded  transversely,  figure  14,  page  19.  Its  concavity  is  divided 
into  two  portions  by  a  distinct  median  vertical  ridge.  The  foramen 
magnixm,  also,  is  expanded  transversely,  and  is  of  moderate  size.  The 
occipital  condyles  are  more  elevated  than  in  Dinoceras  mirahile,  a  line 
joining  their  uppeV  margins  passing  entirely  above  the  foramen  magnum. 

In  Dinoceras  agreste  (number  1221),  a  third  type  of  occiput  is  seen, 
much  more  expanded  above,  as  shown  in  figure  15,  page  19.  The  foramen 
magnum  is  here  subtriangular  in  outline,  and  the  occipital  condyles  are 
placed  similarly  to  those  of  Dinoceras  mirahile. 

In  the  genus  Tinoceras,  two  distinct  types  of  occiput  are  represented 
in  the  Yale  Museum.  In  Tinoceras  ingens  (number  1041),  the  occiput  is 
greatly  elevated,  somewhat  concave  above,  and  expanded  at  the  sides. 
There  is  no  median  crest.  .  The  foramen  magnum  is  triangular  in  outline, 
and  comparatively  small,  with  its  upper  border  lower  than  the  superior 
margins  of  the  occipital  condyles,  as  seen  in  figure  17,  page  19. 

In  Tinoceras  piignax  (number  1044),  the  occiput  is  less  elevated,  and 
more  nearly  quadrate  in  outline.  The  foramen  magnum  is  large,  and 
transversely  expanded.  The  occipital  condyles  extend  above  its  upper 
margin,  as  shown  in  figure  18,  page  19.  In  other  species  of  the 
Dinocerata,  the  occiput  shows  an  equal  variety  of  forms. 

In  Dinoceras  mirahile  (number  1036),  there  is  a  small,  but  distinct, 
par-occipital  process  of  the  ex-occipital,  directed  downward  and  outward. 


THE   SKULL. 


21 


In  the  type  of  Uintatheriuni,  tliis  process  appears  to  be  nearly  obsolete. 
In  front  of  this  process  is  the  sutnre  uniting  the  ex-occipital  directly  with 
the  squamosal,  thus  excluding  the  mastoid  from  the  external  surface  of 
the  skull,  as  in  Rhinoceros.  Tlie  tympanic  portion  of  the  periotic,  also, 
does  not  reach  the  external  surface. 


Pig.  21. 


Fig.  20. 


Figure  19. — Side  view  of  skull  of  Tinoceras  pugnix,  Marsh  (So.  104J). 
FiQDRE  20. — Anterior  part  of  skull  of  Tinoceras  grande.  Marsh  (No.  1040). 
Figure  21. — Anterior  part  of  skull  of  Tinocems  anneclens ,  Marsh  (No.  1043). 

m'.  maxillary  protuberauce;  me.  extcrn;il  auditory  meatus  ;  b'.  nasal  protuberance;    o.  occipilal  condyle; 

p'.  parietal   protuber.nnce ;   pm.  prema.'cillary  bone;    pn.  prcuasal  ossicle. 
All  the  figures  aie  one-eicrlitli  n  itural  size. 


22  DINOCERATA. 

The  Squamosal  Bones. 

The  sqiaamosal  forms  the  lower  portion  of  the  temporal  fossa,  and 
sends  down  a  massive  post-glenoid  process  (Plate  II,  s),  which  bounds 
in  front  the  external  auditory  meatus.  The  latter  has  for  its  posterior 
border  the  post-tjanpanic  process  of  the  squamosal,  -which  unites  directly 
with  the  par-occipital  process  by  close  suture. 

The  periotic  and  tympanic  bones  are  co-ossified,  bnt  not  with  the 
squamosal.  The  periotic  has  a  distinct  floccular  fossa  on  its  inner  side. 
The  tympanic  is  small,  and  is  not  expanded  into  a  distinct  bulla. 

The  squamosal  sends  forward  a  strong  zygomatic  process,  which 
resembles  that  in  Tcqnrus.  This  process  overlaps  the  malar,  uniting  to 
it  by  a  straight,  horizontal,  suture,  which,  in  very  old  animals,  may  nearly 
or  quite  disappear. 

The  Malar  Bones. 

The  malar  bone  completes  the  anterior  portion  of  the  zygomatic  arch, 
extending  to  the  front  of  the  orbit,  as  shown  in  Plate  II,  ma.  Tlie  suture 
uniting  the  malar  with  the  maxillaiy  remains  distinct  till  adult  life,  and 
may  usually  be  traced,  even  in  old  animals.  This  forward  extension  of 
the  malar  bone  is  a  general  ungulate  character,  and  quite  diff'erent  from 
what  is  seen  in  the  Pi'oboscidians,  where  the  malar  forms  the  middle 
portion  only  of  the  zygomatic  arch.  Union  of  malar  with  zygomatic 
process. 

The  Lachrymal  Bones. 

The  lachrvmal  is  large,  and  forms  the  anterior  border  of  the  orbit,  as 
shown  in  Plate  II,  I.  It  is  perforated  by  a  large  foramen.  In  Dinoceras, 
this  opening  is  well  within  the  orbit.  In  some  species  of  Tinoceras,  it  is 
outside  the  orbit.  The  base  of  the  lachrymal  is  excavated  for  the  posterior 
opening  of  the  large  antorbital  foramen. 


THE  SKULL.  23 

The   Maxillaries. 

In  all  the  Binocerata,  the  maxillary  bones  form  a  large  portion  of  the 
lateral  surface  of  the  skull.  They  contain  all  the  teeth,  except  those  of  the 
lower  jaw,  and  also  expand  into  the  large  median  pair  of  osseous  elevations, 
or  horn-cores.  On  the  external  lateral  surface,  the  maxillaries  unite  above 
with  the  frontals  by  suture;  below  this,  with  the  lachrymals,  and  further 
down  with  the  malar.  This  is  well  shown  in  the  figure  of  Binoceras 
mirabile,  Plate  II,  m.  In  front,  the  maxillaries  unite  with  the  pre- 
maxillaries  by  a  nearly  straight,  and  nearly  vertical,  suture.  Above, 
they  join  the  nasals,  as  already  described. 

Tlie  large  canine  tusk  is  entirely  enclosed  in  the  maxillary,  and  in  the 
genus  Binoceras  its  root  extends  upward  into  the  base  of  the  maxillary 
horn-core.  In  all  known  Binocerata,  there  is  a  diastema  between  the  upper 
canine  and  the  pre-molars.  The  latter  are  small,  and  form  with  the  molars 
a  continuous  series.  On  their  inner  surface,  the  maxillaries  send  in  strong 
palatine  plates,  which  meet  on  the  median  line.  The  maxillary  is 
perforated  by  a  large  antorbital  foramen,  the  outlet  of  which  is  concealed, 
in  the  side  view  of  the  skull,  by  a  ridge  extending'  upward  in  front  of  the 
orbit.     Its  position  is  shown  in  figures  22-24,  c,  page  25. 

The  Premaxillaries. 

The  2^i'6niaxillary  bones  are  edentulous,  and,  even  in  young 
specimens,  contain  no  teeth.  These  bones  have  three  distinct  branches, 
the  largest  of  which  extends  well  forward  below  the  anterior  nasal 
opening.  The  second  branch  also  extends  forward  above  this  opening, 
forming  Avith  the  nasal  its  superior  border,  as  shown  in  the  type  of 
Binoceras  mirabile,  Plate  II,  jjm.  The  third  branch  is  a  horizontal  plate 
extending  inward  to  the  median  line,  where  it  joins  its  fellow,  and  thus 
completes  the  anterior  portion  of  the  palate. 

The  anterior  free  portions  of  the  premaxillaries  are  well  separated  on 
their  palatal  surface,  but  these  bones  meet  somewhat  in  front  of  the  anterior 


24  DINOCERATA. 

palatal  foramina.  Near  this  point,  the  palatine  plates  are  united  by 
suture  on  tlie  median  line,  and  this  suture  is  continued  backward  along 
the  palate  until  it  meets  with  the  median  suture  between  the  maxillaries. 
The  anterior  palatine  foramina  are  narrow  fissures,  rounded  in  front,  and 
separating-  the  lateral  jiortions  of  the  premaxillaries  from  the  palatine 
plates,  as  in  Equus.  The  latter  plates  unite  posteriorly  by  suture  with 
the  adjoining  maxillaries,  as  shown  in  Plate  V,  pm. 

The  premaxillaries  vary  much  in  form  in  the  different  genera  and 
species  of  Dinocerata.  Two  of  the  principal  forms  in  the  genus  Dinoceras 
are  shown  in  figures  26  and  27,  page  26,  and  two  of  the  genus  Tinoceras, 
in  figures  28  and  29,  on  page  27. 

The  Palate. 

In  all  the  Dinocerata,  the  palate  is  very  nnrrow,  and  much  excavated, 
especially  in  front.  The  bony  palate  extends  back  as  far  as  the  last 
upper  molar,  and  in  some  specimens  beyond  it.  Eacli  maxillary 
articulates  with  the  corresponding  premaxillary  by  a  suture  commencing 
on  the  palatal  surface,  in  front  of  the  lai-ge  canine  alveolus,  and  running 
just  within  the  border  of  tile  alveolus  to  near  the  middle  of  its  inner 
margin.  At  this  point,  the  suture  turns  inward,  across  the  end  of  the 
main  branch  of  the  premaxillary,  and  then  obliquely  backward,  along  the 
posterior  end  of  its  palatine  plate.  The  median  suture  is  continued 
backward,  separating  the  maxillaries,  to  a  point  nearly  opposite  the 
middle  of  the  penidtimate  molar,  where  the  maxillaries  join  the  palatines. 
The  maxillo-palatine  suture  is  at  first  transverse,  extending  across  the 
palate  nearly  to  the  alveolar  border  of  the  maxillary,  and  is  then  continued 
backward  near  this  border,  and  around  behind  the  last  molar,  whence  it 
tm'Ds  outward,  and  ascends  the  side  of  the  skull  in  the  orbital  region. 

The  ]ialatal  surface  of  each  maxillary  is  deeply  excavated  in  front 
between  the  canines,  along  the  diastema,  and  as  far  back  as  the  second  or 
third  premolar ;  but  on  the  median  line  these  bones  meet  in  a  sharp  ridge, 
nearly   on   a  level   with   the   outer  opposite  border  of  the  maxillaries. 


THE   SKULL. 


25 


FlQ.  23. 


Fig.  24. 


Figure  22.— Anterior  part  of  pal.ite  of  Dinoceras  laiiceps,  Marsh  (No.  1039). 

Figure  23.  — Anterior  part  of  palate  of  Tinoceras  ingens,  Marsh  (No.  1041). 

Figure  24. — Anterior  part  of  palate  of  Tinoceras  pugnax,  Marsh  (No.  1044). 

FlGtJEE  25. — Anterior  part  of  palate  of  Hippopotamus  amphibius,  Linnsiis. 

a.  anterior  palatine  foramen;    6.  lalatb-maxillary  foramen;  c.  antorbital  foramen ;  d.  alveole  i 
TO.  maxillary  bones ;  B.  nasal  bones  ;  pm.  premaxiUary  bones;  pn.  prenasal  ossicles. 
All  the  figures  are  one-fifth  natural  size. 


26 


DINOCERATA. 


The  bony  palate  is  thus  deeply  excavated  on  each  side  in  the 
region  of  the  diastema,  and  near  the  posterior  part  of  each  excavation  on 
either  side  is  situated  a  large  foramen,  which  may  be  called  the  palato- 
maxillary foramen.  This  foramen  is  shown  in  Plate  V,  and  also  in  figures 
22—24,  h,  page  25.     The  same  foramen  is  seen,  also,  in  the  hippopotamus. 


FietTEE  26. — Skull  of  Dinoceras  mirabile,  Marsh  (No.  1036);  seen  from  below. 
KlUURB  27. — Skull  0? Dinoceras  laticeps,  Marsh  (No.  1039);  same  view. 

a.  anterior  palatine  foramen;  J.  palato-maxiUary  foramen ;    c.  antorbital  foramen;   d.  posterior   palatine 

foramen;    e.  posterior    nares ;   /.  foramen   maguum ;  /'.  occipital   foramen;    g.  stylomastoid    foramen; 

A.  foramen  lacerum  posterins;   «.  vascular  foramen  in  basisphenoid  ;  j.  posterior  opening  of  alisphenoid 

canal ;  k.  anterior  opening  of  alisphenoid  canal;  I.  optic  foramen. 

Botli  figures  are  one-eighth  natiu'al  size. 

The  palatine  surface  of  the  maxillary  bone  is  perforated  with  small 
foramina,  along  the  line  of  the  enclosed  canal,  as  in  the  hippopotamus, 
evidently  for  the  transmission  of  blood-vessels  and  nerves  to  the  gums 
and  surface  of  the  palate. 


THE   SKULL. 


2T 


The  maxillary  bones  contain  the  sockets  of  all  the  npper  teeth.  The 
socket  for  the  canine  is  a  large  and  deep  cavity,  elong-ate-oval  in  section, 
and  extending  upward  and  backward  to  the  posterior  part  of  the  base  of 
the  large  maxillary   protuberance.     The   outer  surface   of  the   maxillary 


Figure  28. — Skull  of  Tinoceras  ingens,  Marsh  ;  seen  from  belovr. 
Figure  29. — Skull  ot  Tinocefas pngnax,  Marsh;  same  Tiew. 

a.  anterior  palatine  foramen;  &.  palato-maxillary  foramen;  c  antoibital  foramen;   (?.  prsterior  palatine 

foramen;    e.  posterior  nares;   /.  foramen    magnum;   /'.  occipital   foramen;    g.  stylo-mastoid   foramen; 

h.  foramen   lacernm  ;    i.   vascular  foramen  in  basisphenoid  :  j    posterior  opening  of  alisphenoid  canal ; 

k.  anterior  opening  of  alisphenoid  canal ;  /.  optic  foramen. 

Tolh  figures  are  one-fighth  natural  size. 


28  DINOCEKATA. 

bone  is  swollen  by  this  socket,  so  as  to  present,  in  the  males  at  least,  a 
prominent  rounded  ridge  on  the  side  of  the  face.  The  alveoli  for  the  pre- 
molar and  molar  series  of  teeth  are  similar  to  each  other,  each  presenting 
three  pits  for  the  reception  of  roots,  viz :  an  inner  large  pit,  and  two  outer 
small  ones.  Over  these,  the  bone  is  thin,  as  is  usual  on  the  buccal  surface 
of  the  maxillary. 

Behind  and  above  the  posterior  molar  teeth,  in  the  orbital  region  of 
the  skull,  the  maxillary  bone  j^resents  several  fissures,  or  foramina,  close 
to,  or  in,  the  suture  with  the  palatine.  The  first  of  these  may  be  indistinct, 
or  of  different  shape  on  the  opposite  sides,  and  is  just  back  of  the  last 
molar,  as  shown  in  the  skull  of  Dinoceras  lucare,  on  Plate  IX,  figure  2. 
In  Dinoceras  mirabile  (number  1036),  three  such  fissures  are  situated  on  the 
right  side  of  the  skull,  in  or  near  the  maxillo-palatine  suture,  back  of  the 
orbit.  One  or  more  of  these  apertures  appear  to  be  the  posterior  openings 
of  the  posterior  palatine  foramina,  an  arrangement  similar  to  that  seen  in 
the  hippopotamus. 


The  Palatine  Bones. 

The  palatine  bones  form  only  a  small  part  of  the  bony  palate  in 
Dinoceras.  The  palato-maxillary  suture  in  Dinoceras  mirabile  (number 
1036)  Is  nearly  opposite  the  middle  of  the  second  molar,  and  about  20™™ 
in  front  of  the  posterior  border  of  the  bony  palate,  (Plate  V).  It  is  at  first 
nearly  transverse  to  the  palate,  then  runs  backward  around  the  last  molar, 
and  turns  upward  into  the  orbital  region,  where  it  cannot  be  followed  with 
certainty.  Posteriorly,  the  palatine  is  in  contact  with  the  pterygoid,  and 
the  pterygoid  plate  of  the  alisphenoid.  On  the  median  line  of  the  palate, 
the  suture  between  the  opposite  palatines  is  obliterated. 

The  palatines  continue  the  lateral  walls  of  the  posterior  nasal  cavities 
considerably  behind  the  last  molar,  and  these  walls  are  still  further 
extended  by  the  pterygoid  bones. 


THE   SKULL. 


29 


The  Pterygoid  Bones. 

The  pterygoid  bones  in  Dinoceras  ndrahile  (number  1036),  are  applied 
to  the  inner  surface  of  the  palatines,  and  to  the  pterygoid  plates  of  the 
alisphenoid  (Plate  V,  pt).  They  appear  to  unite  on  the  median  line  in  the 
roof  of  the  posterior  nares,  but  the  sntui-e  is  not  distinct.  The  suture  with 
the  palatine  is  oblique,  and  that  with  the  alisphenoid  can  be  traced  upward 
beneath  the  zygomatic  arch. 

The  lower  margin  of  the  pterygoid  is  thickened,  and  nearly  straight 
The  posterior  margin  is  thinner,  and  moderately  curved. 


PlGUBE  30. — Horizontal  section  of  skull  of  Tinoceras  crassifrons.  Marsh  (No.  1236). 

Figure  31. — Horizontal  section  of  skull  of  Dinoceras  riistans,  Marsli  (Xo.  1601). 

a  cjvity  beliiud  base  of  on  cine  tooth;  b.  brain-cavity;  c.  alvO'le  of  canine  tooth; /■  anterior  olfactory 
chamber ;  /'.  posterior  olfactory  chamber ;  m'.  maxillary  protuberance ;  n.  nasal  bones ;  «'.  nasal 
protuberance ;  p'.  parietal  prutuberaoces. 

Both  figures  are  cne-ei^lith  natural  size.  ■ 


30 


DINOCERATA. 


In  the  skull  of  Tinoceras  ingens  (number  1041),  the  palate  is  only 
slightly  excavated  in  its  anterior  part,  and  the  palato-maxillary  foramina 
are  brought  forward  in  front  of  the  entire  series  of  molar  teeth,  instead  of 
being  situated  nearly  opposite  the  second  premolar.  The  palate  between 
the  Avhole  sei'ies  of  molar  teeth  is  nearly  flat.  The  foramen  in  the  maxillo- 
palatine  suture  behind  the  last  molar  is  large  and  conspicuous,  especially 
on  the  left  side.     These  foramina  are  shown  in  figure  28,  page  27. 


Figure  32. — Horizontal  spction  of  skull  of  Tinoceras  Mans,  Marsli  (No.  1499). 

Fl&nBK  33. — Horizontal  section  cf  skull  of  Dinoctras  laticeps,  Marsli  (No.  1202),  female. 

a.  cavitj'  behind  base  of  canine  too;h;  h.  brain-cavity;  c.  alveole  of  canine  tooth  ;  /  anterior  olfactory 
chamber;  /'.  posterior  olfactory  chamber;  tn'.  maxillary  protuberance;  ii.  nasal  bones;  n'.  nasal 
protuberances  ;  p'.  parietal  protuberances. 

Both  figures  are  one-eighth  natural  size. 

In  the  type  of  Tinoceras  grancle  (number  1040),  the  maxillo-palatine 
foramen  is  behind  the  beginning  of  the  molar  series,  and  the  excavation  of 
the  palatal  region  also  extends  behind  the  first  premolars. 


THE   SKULL. 


31 


In  the  tj-pe  of  Dinoceras,  the  palatine  fossa  of  the  posterior  nares  is 
roofed  over,  so  that  the  passage  from  the  palate  into  the  large  nasal 
cavities  above  leads  forward  and  upward,  as  shown  indistinctly  in  figure 
26,  e,  page  26.  In  Tinoeeras  ingens  and  Tinoceras  pugnax,  the  roof  of  this 
fossa  is  excavated  in  front  by  a  pair  of  oval  apertures,  and  through 
these  the  posterior  nares  open  directly  upward,  as  re^Dresented  in  tigures 
28  and  29,  e,  on  page  27.  The  existing  perissodactyls,  the  liorse,  the 
tapir,  and  rhinoceros,  have  the  same  type  of  palate.  In  Uintatheriuni,  the 
structure  of  this  portion  of  the  skull  has  not  yet  been  determined  with 
certainty. 


FiGUBE  34. — Vertical  median  longitiviinal  section  of  skull  o(  Dinoceras  miraiile,  Marsh. 

Figure  35.  -Vertical  transverse  section  of  sl\ull  of  Dinoceras  mirdbiU. 

b.  brain-cavity ;  c.  cavities  in  cranial  vi'alls ;  /.  frontal  bone ;  m.  maxUlary  bone ;  to'.  ma.Tillary  protuber- 
ance ;  ji.  nasal  bone  ;  «'.  nasal  protuberance  ;  o.  occipital  condyle  ;  oi.  olfactory  lobes  of  ljr„iu  ;  o;.).  optic 
foramen;  p.  parietal  bone;  p'.  parietal  protuberance;  jjg.  post-gleiioid  process;  pi.  palatine  bone; 
pm.  premaxflary  bone;  pt.  pterygoid  bone;  s.  supra-occipital  crest;  2.  zygomatic  process  of  squamosal. 

Both  figures  are  one-eighth  natural  size. 


These  palatine  characters  of  the  JDinocerata  are  important,  but 
unfortunately  they  can  be  made  out  only  in  skulls  unusually  well 
preserved.  The  value  of  these  characters  in  classification  will  be 
discussed  in  a  subsequent  chapter 


32  DINOCERATA. 


The  Vomees. 

The  A'omers  iia  the  JDinocerata  do  not  appear  upon  the  surface  of  the 
palate.  They  are  narrow  bones,  closely  united,  and  deeply  concave  upon 
then-  upper  surface.  They  are  wedged  in  between  the  palatine  plates  of 
the  maxillaries,  and  in  old  animals  are  closely  united  with  them. 

The  groove  formed  by  the  upper  concave  surfaces  of  the  vomers  is 
filled  by  the  turbinal  bones,  Avhich  are  well  developed. 

The  following  are  the  principal  dimensions  of  three  of  the  skulls 
described  in  the  present  chapter.  Measiu-ements  of  others  will  be  found 
in  the  Synopsis  at  the  end  of  the  volume  : 

Measurements  of  Skull.     [Diiioceras  mirahile,  ISTo.  1036.) 

m. 

Total  length  of  skull  from  nasals  to  occipital  crest, .   . . 0.76 

Total  length,  from  preniaxillaries  to  occipital  condyles, 0.66 

Greatest  transverse  diameter,  through  parietal  protuberances, _  0.385 

Greatest  transverse  diameter,  through  occipital  crest, ^ 0.26 

Greatest  transverse  diameter,  through  maxillary  protuberances, 0.205 

Least  transverse  diameter,  behind  maxillary  protuberances, 0.155 

Greatest  transverse  diameter,  through  zygomatic  arches, 0.285 

Greatest  transverse  diameter,  through  post-glenoid  processes, 0.25 

Length  of  palate,  from  end  of  premaxillaries  to  posterior  narcs, 0.35 

Length  of  palatine  bone,  on  median  line, _. - --  0.030 

Length  of  maxillary  bone,  on  median  line, 0.185 

Width  of  jialate,  between  last  molars, .- 0.050 

Width  of  palate,  between  first  molars. 0.065 

Width  of  palate,  between  first  premolars, 0.050 

Width  of  palate,  across  diastema, 0.07 

Width  of  palate,  between  canines, ._- 0.105 

Antero-posterior  diameter  of  zygomatic  fossa, . —  0.165 

Transverse  diameter  of  zygomatic  fossa, 0.08 

Distance  from  top  of  parietal  protuberance  to  end  of  post-glenoid  process,.. _  0.37 

Distance  from  top  of  maxillary  protuberance  to  end  of  canine, 0.415 

Vertical  diameter  of  foramen  magnum, _  - . ,-  - -,---,  0.05 1 

Transverse  diameter  of  foramen  magnum, 0.065 


THE  SKULL.  33 


Measurements  of  Skull.     (7'inoceras  ingens,  No.  1041.) 

m. 

Total  length  of  skull  from  nasals  to  occijjital  crest, 0.87 

Total  length,  from  firemaxillaries  to  occipital  condyles, _. 0.815 

Greatest  transverse  diameter,  through  parietal  protuberances, 0.47 

Greatest  transverse  diameter,  through  parietal  angles  of  crest, 0.33 

Greatest  transverse  diameter,  through  maxillary  protuberances, 0.35 

Least  transverse  diameter,  behind  maxillary  protuberances, 0.21 

Greatest  transverse  diameter,  through  zygomatic  arches, 0.37 

Greatest  transverse  diameter,  through  post-glenoid  processes, 0.30 

Length  of  palate,  from  end  of  premaxillaries  to  posterior  nares, 0.40 

Width  of  palate,  between  last  molars, 0.064 

Width  of  palate,  between  first  molars, .    0.065 

Width  of  palate,  between  fii-st  premolars, 0.056 

Width  of  palate,  across  diastema, 0.09 

Width  of  palate,  between  canines, .    _.... 0.10 

Antero-posterior  diameter  of  zygomatic  fossa, .  _ 0. 1 9 

Transverse  diameter  of  zygomatic  fossa, __. 0.08 

Distance  from  top  of  parietal  protuberance  to  end  of  post-glenoid  process, 0.52 

Vertical  diameter  of  foramen  magnum, _ _. 0.075 

Transverse  diameter  of  foramen  magnum, 0.045 


Measivrements  of  Skull.      (Tinoceras  jmgiia.r,  No.  1044.) 

m. 

Total  length  of  skull  from  nasals  to  occipital  crest, .  0.77 

Total  length,  from  premaxillaries  to  occipital  condyles, 0.665 

Greatest  transverse  diameter,  through  parietal  jDrotuberances, '. 0.425 

Greatest  transverse  diameter,  through  parietal  angles  of  crest, 0.305 

Greatest  transverse  diameter,  through  maxillary  protuberances,...    0.265 

Least  transverse  diameter,  behind  maxillary  protuberances, 0.19 

Greatest  transverse  diameter,  through  zygomatic  arches, . 0.34 

Greatest  transverse  diameter,  through  post-glenoid  processes, 0.28 

Length  of  palate,  from  end  of  premaxillaries  to  posterior  nares, 0.33 

Width  of  palate,  between  last  molars, 0.084 

Width  of  palate,  between  first  molars, 0.084 

Width  of  palate,  between  first  premolars, 0.056 

Width  of  palate,  across  diastema, _.. 0.096 

Width  of  palate,  between  canines, 0.132 

Antero-posterior  diameter  of  zygomatic  fossa, 0.12 

Transverse  diameter  of  zygomatic  fossa, 0.096 

Distance  from  top  of  parietal  protuberance  to  end  of  post-glenoid  process, 0.37 

Distance  from  top  of  maxillary  protuberance  to  end  of  canine,  about.-,    0.48 

Vertical  diameter  of  foramen  magnum, 0.050 

Transverse  diameter  of  foramen  magnum, 0.075 

5 


CHAPTER    II, 


THE   LOWER  JAW. 

(Plates  VIII,   XII,    XIII,   XIX,  LV,   and    LVI.) 

The  lower  jaw  in  JDinoceras  is  as  )-eniarkable  as  the  skull.  Its  most 
peculiar  feature  in  the  male  is  a  massive  decurved  process  on  each  ramus, 
extending  downward  and  outward.  These  long  pendent  processes  were 
apparently  to  protect  the  upper  canine  tusks,  which  would  otherwise  be 
very  liable  to  be  broken  (Plate  XIII,  figures  1  and  2,  p).  Indications  of 
similar  processes  are  seen  in  Smilodon,  and  in  some  other  extinct  carnivors 
with  long  canines. 

In  Dinoceras  mirabile  (number  1212),  the  process  is  concave  from  above 
downward  on  its  external  surface,  and  its  lower  extremity  is  somewhat 
thin,  and  narrowed  longitudinally.  In  Dinoceras  laticeps  (Plate  XIII, 
tigures  1  and  2,  p),  this  process  is  more  massive,  and  more  rounded  below. 

In  the  female,  this  process  is  much  reduced  in  size,  but  is  quite 
sufficient  to  protect  the  diminutive  tusk,  which  overlaps  it. 

With  the  exception  of  these  processes,  the  lower  jaw  is  comparatively 
small  and  slender.  The  symphysis  is  completely  ossified,  and  deeply 
excavated  above. 

Another  remarkable  feature  in  the  lower  jaw  of  the  Dinocerata  is  the 
posterior  direction  of  the  condyles,  hitherto  unknown  in  Ungulates  (Plate 


36 


DINOCERATA. 


VIII,  figure  1,  cd).  The  position  of  the  condyles  was  evidently 
necessitated  by  the  long  upper  tusks,  since  with  the  ordinary  ungulate 
articulation  the  mouth  could  not  have  been  fully  opened.  The  low 
position  of  the  condyle,  but  little  above  the  line  of  the  teeth,  is  also  a 
noteworthy  character.  In  some  Marsupials  and  Insectivors,  the  condyle 
has  the  same  position  as  in  the  JDinocerata,  but  in  no  other  Ungulates, 
living  or  extinct,  has  this  position  been  observed. 


frr 


PiGTJRE  36. — Lower  jaw  of  Tinoceras  annectens,  Marsh  (No.  104:-!);  seea  from  the  left. 
Figure  ST. — The  same  jaw,   seen  from  above. 

c.  alveole  of  lower  canine;    d.  diastema;    i.  alveole  of  incisor;    m.  mental   foramen; 

protection  of  canine  tusk  ;  s.  symphysis. 

Both  figures  are  one-fourth  natural  size. 


In  Dinoceras  laficeps  (Plates  XII  and  XIII),  the  entire  lower  jaw  is 
more  massive  than  in  Dlnoceras  mirahile.  The  angle  of  the  jaw  is  stouter, 
and  distinctly  inilected  (Plate  XIII,  figure  2,  a.) 


THE   LOWER   JAW. 


37 


The  coronoid  process  of  the  lower  jaw  in  Dinoceras  is  large  and 
elevated,  somewhat  curved  backward,  and  pointed  above  (Plate  VIII, 
fig-ure  1,  cr).  The  angle  of  the  jaw  is  rounded  in  outline,  and  projects 
downward  somewhat  below  the  main  portion  of  the  ramus.  The  dental 
foramen  is  large,  and  bounded  above  by  a  ridge,  which  extends  upward 
and  backward  to  the  condyle.  The  mental  foramen  is  of  moderate  size, 
and  situated  near  the  base  of  the  anterior  pendent  process. 


Figure  38. — Lower  jaw  witli  upper  canine  in  position  of  Tiaoceras  lo/iyiceps,  Msrsh  (No.  1256),  female;  seen 
from  the  left. 

a.   angle  of  jaw;    c,  upper  canine  tooth  in  its  natural   position;    c'.  lower  canine  tooth;    cd.  condyle; 
cr.  coronoid  process;    d.  diastema;  p.  process  for  protection  of  canine  tusls. 
One-fourth  natural  size. 


In  the  genus  Tinoceras,  the  same  general  characters  of  the  lower  jaws 
are  seen.  In  the  male,  the  pendent  process  is  lai-ge  and  elongate,  but  less 
massive  than  in  the  genus  Dinoceras,  and  its  lower  outline  less  regularly 
rounded  (Plate  XIX,  figure  1,  q:)).  This  corresponds  with  the  position  of 
the  large  upper  canine  tusk,  which  it  protects. 

In  the  female  of  Tinoceras,  the  pendent  j^i'ocess  is  much  reduced,  its 
size  in  all  cases  corresponding  to  the  size  of  the  canine  tusk  above.  In 
the  female  of  Tinoceras  longiceps  (figure  38,  above),  the  lower  jaw  is 
remarkably  long-  and  slender,  and  the  pendent  process  nearly  obsolete. 


38 


DINOCEHATA. 


Tliat  tlie  same  relation  in  size  between  tlie  tusk  and  process  below 
it  holds  equally  in  both  the  genera  Binoceras  and  Tinoceras,  is 
conclusively  shown  by  various  specimens  in  the  Yale  Museum. 


Figure  .39. — Lower  jaw  ot  Dinoceras  mirahile,  Marsh  (No.  1251);  seen  from  tlie  left. 
FiGDEE  40. — The  same  jaw;  seen  from  the  front. 

c.  alveole   of  caniue;    /.  auterior    foramen;    di.  deciduous    iucisor;    i.  alveole   of   incisor;     rii.    mental 

foramen ;  p.  process  for  protection  of  tusk. 

Both  fiffureg  are  one-fourth  natural  size. 


In  the  genus  Dinoceras,  there  are  three  incisor  teeth,  and  a  small 
incisiform  canine  on  each  side  forming  a  continuous  series  at  the  front 
extremity  of  the  lower  jaw.  These  are  all  of  moderate  size,  and  inclined 
well  forward,  as  in  the  ruminant  mammals.  Behind  this  series,  and 
immediately  over  the  dependent  process,  is  a  long  diastema  (Plate  VIII, 
figure  1,  d).  Further  back,  there  are  three  premolars,  and  three 
molars,  forming  together  a  close  series.  .  This  is  the  dentition,  essentially, 
in  the  lower  jaw  of  both  Dinoceras  and  Tinoceras,  and  will  be  described 
more  fully  in  the  following  chapter. 

In  a  lower  jaw  found  near  the  locality  of  the  type  of  Uintatherium 
rohishim,  and  here  referred  to  that  genus,  there  are  four  premolars  instead 
of  three.  Tlie  first  pi-emolar,  wanting  in  Dhioceras  and  Tinoceras,  is  of 
small  size,  and  is  placed  just  behind  the  lower  canine.  It  is  separated 
from  the  second  premolar  by  a  diastema,  as  shown  in  figures  41  and  42, 
page  39. 


THE   LOWER   JAW. 


39 


In  the  present  state  of  knowledge  of  the  Dinocerata,  this  first  lower 
premolar  may  be  regarded  as  a  distinctive  feature  of  the  genus 
Uintatherium,  the  type  specimen  of  which,  iinfortunately,  is  too 
fragmentary  for  a  complete  identification  of  its  principal  characters. 


PlGUBB  41. — Lower  jaw  of  Uintailierium  segne.  Marsh  (No.  1194);   seen  fiom  the  left. 
Figure  42. — The  same  jaw;   seen  froQi  above. 

a.  angle;  c.  alveole  of  canine ;   cr.  ooronoid  process;   cd.  condyle;  d.  diastema;  p.  process  for  protection 

of  tusk ;   pm.  alveole  of  premolar 

Both  figures  are  one-fourth  natural  size. 


40  DINOCERATA. 

The  principal  dimensions  of  thi^ee  of  the  lower  jaws  described  in  this 
chapter  are  as  follows  : 

Measurements  of  Lower  Jaw.     {D'moceras  laticeps.  No.  1039.) 

m. 

Greatest  length  of  ramus, 0.54 

Extent  of  symphysis, — 0.18 

Height  of  eoronoid  process  from  bottom  of  ramus, ._. 0.235 

Depth  of  ramus  at  last  molar, — 0.09 

Depth  of  ramus  at  tusk  process, , : 0.185 

Extent  of  diastema, .-.    0.10 

Extent  of  molar  series,  -  0.18 

Greatest  width  across  condyles, . 0.295 

Transverse  diameter  of  condyle, —    0.087 

Vertical  diameter  of  condyle, —  .- _-.  0.048 

Measurements  of  Lower  Jaw.     (Uintatherlum.  segne.  Marsh,  No.  1194.) 

m. 

Greatest  length  of  ramus, .-.    0.49 

Extent  of  symphysis,    _   0.165 

Height  of  coronoid  process  from  bottom  of  ramus  (approximate), 0.1 9 

Depth  of  ramus  at  last  molar, 0.075 

Depth  of  ramus  at  tusk  process, . —  0. 17 

Extent  of  molar  series  (functional), ._    .-.- 0.145 

Transverse  diameter  of  condyle, ., 0.076 

Vertical  diameter  of  condyle, .._.. .. 0.040 

Measurements  of  Lower  Jaw.     (Tinoceras  lougiceps,  Marsh,  No.  1256,  female.) 

m. 

Greatest  length  of  ramus  (approximate), .__. _. 0.57 

Extent  of  symphysis, _. 0.185 

Height  of  coronoid  process  from  bottom  of  ramus, ..  0.26 

Depth  of  ramus  at  last  molar, ..  0.084 

Depth  of  ramus  at  tusk  process, 0.10 

Extent  of  diastema, 0.145 

Extent  of  molar  series, . ... ..    . 0.175 

Transverse  diameter  of  condyle, . . -.    --    0.070 

Vertical  diameter  of  condyle, 0.045 


CHAPTER    III. 


THE   TEETH. 


(Plates  I-V,  VII-X,  XII-XIX,  LV  and  LVI.) 

The  teeth  of  the  Dinocerata  constitute  one  of  their  most  interesting 
features,  differing-  widely  in  form  and  dentition  from  most  of  the  other 
Ungulata. 

In  the  genus  Dinoceras  the  dentition  is  represented  by  the  following 

formula  : 

T     .  0  .1  T  3  1        3 

Incisors  — ,    canmes  — ,    premolars    — ,    molars  —  =r  34. 
3  1  3  3 

So  far  as  now  known,  the  same  formula  applies  equally  well  to  the 
genus  Tinoceras. 

In  Uintatherium,  the  dentition  is  apparently  as  follows: 

T     .  0  .1  1  3  ,         3 

incisors  — ,    canines  — ,    premolars    — ,    molars  --  i^;  36. 
3  1  4  3 


The  Incisoes. 

Ill  none  of  the  Dinocerata  have  any  upper  incisors  been  found,  even 
in  the  youngest  specimens.  The  premaxillary  bones  appear  to  be 
entirely  edentulous,  although  in  some  specimens,  especially  in  Dinoceras 
laticeps  (number  1039),  there  are  shallow  depressions  at  irregular  intervals 
that  strongly  suggest  the  ^probability  of  embryonic  teeth  in  very  young,  or 
foetal  individuals. A  fortunate  discovery  in  the  future  may,  perhaps,  settle 
this  point. 


42 


DINOCERATA. 


In  the  lower  jaws  of  all  the  known  Dlnocerata,  there  are  three  well- 
developed  incisors  on  each  side.  They  are  inserted,  each  by  a  sing-le  root, 
and    are   procumbent,    all    directed  well  forward.      Their   inner  surfaces 


Figure  43. — Incisor  of  Dinoceras  mirahile,  Marsh  (No.  1491). 
FiGUKE  44 — lucisor  of  Dinoceras  mirahile  (No.  1492). 
Figure  45. — Incisor  of  Dinoceras  mirahile  (^o.  1490). 

a.  side  view;  h.  top  view;   c.  antero-postorior  view. 

All  the  fignres  are  of  natural  size. 


THE   TEETH. 


43 


continue  tlie  deep  groove  on  the  upper  part  of  tlie  lower  jaw,  above  the 
symphysis.  Tlie  position  of  the  sockets  for  these  teetli  in  Dinoceras  is 
shown  in  Plates  XII  and  XIII,  and  the  form  of  the  teetli,  in  Plate  VIII, 
figure  1.  The  crowns  of  these  incisors  are  covered  with  enamel,  and  the 
special  features  of  both  crown  and  root  are  shown  in  figures  43-45,  page  42. 
In  the  genus  Tinoceras,  the  incisors  are  similar  in  form,  but  have  a 
less  inclined  position,  as  indicated  in  Plate  XIX,  figure  1. 


lO 


Figure  4G. — Ui)[5er   canine  of  Dinoceras  lucare,  Marsh   (No.  1038);    male.      h.  lateral    view,   inner   surface; 

b'.  outline  of  section  of  tootli ;   b".  section  of  tooth  showing  pulp  cavity;   c.  front  view  of  looth. 
FiGDUE  41. — Upper   canine    oi  Dinoceras    laticeps,    Marsh  (So.    1202);    female,      a.  outer   surface;     b.  inner 

surface  ;    b'.  outline  of  sec  ion  ;  c.  front  view. 
Figure  48.— Upper  canhie  of  Tinocents  hmgiceps,   Marsh  (No.   1256);    female,      a.   outer   surface;    b.   inner 

surface  ;    c.  front  view  of  looth. 

The  dotted  line  on  the  teelli   marks   the  position   of  the  alveolar    border,  below  wliich  the  tusk 

was  exposed. 

All  the  figures  are  one-foicrtli  natural  size. 


The  Canine.s. 
The  superior  canines  of  Dinoceras  are  long,  recurved,  trenchant  tusks. 
The  crown  is  covered  with  enamel,  and  the  I'oot  extends  upward  into  the 
base  of  the  maxillary  protuberance,  or  horn-core.      When  the  animal  is 


44 


DINOCERATA. 


young,  these  tusks  grow  from  a  persistent  pulp,  but  in  old  age  the  cavity 
becomes  nearly  closed.  In  the  male,  these  tusks  are  large  and  powerful, 
and  extend  downward  nearly  or  quite  to  the  extremity  of  the  pendent 
process  of  the  lower  jaw. 


Figure  49. — Upper  canine  of  Tinoceras  grande,  Marsh  (Xo.  lOiO);  male. 
FlGUEE  00. — Upper  cauine  of  Dinoceras  latirejis,  Marsh  (No.  1222) ;  male. 

a.  lateral  view  showing  outer  surface;  i.  inner  surface;  b'.  h".  sections;  c.  front  view. 

The  dotted  Une  on  the  teeth  marks  the  position  of  the  alveolar  border,   below  which  the  tusk 
was  exposed. 

All  the  fisrures  are  one-fourth  natural  size. 


In  Dinoceras  mirabile  (number  1036),  the  canine  tusks  are  oval 
in  section,  where  they  emei'ge  from  the  jaw,  then  become  somewhat 
constricted,  before  expanding  into  a  wide,  thin,  lanceolate  extremity,  as 
shown  in  Plate  I.  On  the  outer  surface  of  these  tusks,  there  is  a  distinct 
ridge  in  the  lower  half  exposed,  g'iving  there  a  subtriangular,  or  ba^'onet- 
like  form. 


THE   TEETH. 


45 


In  Dimceras  liicare,  the  upper  canines  are  not  constricted,  but  taper 
to  the  lower  end,  which  has,  also,  a  bayonet  form  (Plate  IX,  figure  1,  c). 


?  I    I 


^  l£  " 


In  the  female  of  B'moceras,  the  upper  canhies  are  small  and  slender, 
and  protrude  but  little  below  the  jaw  (Plate  XIV,  figure  1,  c). 


46  ■  DINOCERATA. 

In  Tinoceras,  the  upper  canines  are  much  more  curved  than  in 
Dinoceras,  and  the  end  of  the  root,  instead  of  being-  inserted  in  the 
base  of  the  maxillary  horn-core,  starts  well  back  of  it,  so  that  the ' 
general  direction  of  this  elevation  is  nearly  at  right  angles  to  the  tusk. 

The  general  form  of  the  upper  canine  tusks  in  the  Dinocerata  is 
shown  in  figures  49-52,  on  pages  44  and  45. 

In  .the  lower  jaw  of  Dinoceras,  the  canine  is  very  small,  and  very 
similar  in  form  to  the '  incisors,  whicJi  it  adjoins  (Plate  VIII,  figure  1,  c). 
The  same  is  true  in  the  genus  Tinoceras,  where  the  lower  canine,  as  well 
as  the  incisors,  has  a  more  erect  position  than  in  JDinoceras. 


The  Upper  Premolars. 

The  crowns  of  the  premolar  and  molar  teeth  in  Dinoceras,  and,  in 
fact,  in  all  of  the  known  Dinocerata,  are  remarkably  short,  witli  the  roots 
well  developed,  forming  a  true  brachj'odont  dentition,  a,s  in  all  early 
Tertiary  ungulates.  These  teeth  are  all  inserted  by  three  roots,  two  small 
ones  on  the  outer  side,  and  a  larger  one  on  the  inner  side. 

In  the  type  of  Dinoceras  mirabile  (number  1036),  the  upper  molar 
series  is  remarkably  well  preserved.  Tlie  entire  set  of  premolars  and 
molars  is  in  position,  indicating-  that  the  animal  was  fully  adult,  and  yet 
the  amount  of  wear  showir  by  these  teeth  is  so  slight  as  not  to  obscure  in 
the  least  their  essential  characters. 

The  form  and  relative  position  of  the  series  on  the  two  sides  is  well 
shown  in  Plate  VII,  figure  2.  There  are  three  premolars,  and  three  true 
molars  on  each  side,  forming  together  a  close  series.  There  is,  in  this 
skull,  no  trace  of  what  may  be  regarded  as  the  first  premolar.  If  present 
during  the  immature  condition  of  the  animal,  it  has  entirely  disappeared. 
In  one  specimen  of  this  genus  (number  1039),  the  alveole  of  this  first 
upper  premolar  remains,  but  no  other  trace  of  the  tooth  has  been  seen. 

The  first  premolar  of  Dinoceras  mirahile  in  place,  which  would 
correspond   to   the    second   in   the    complete   ungulate    dentition,    is   the 


THE   TEETH. 


47 


smallest  of  the  present  series.  Its  crown  is  subtriangular  in  outline,  with 
the  apex  in  front.  The  antero-external  face  is  cordate  in  outline, 
somewhat  concave,  with  the  point  below.  On  the  inner  side,  there  is 
an  elevated  lobe,  somewhat  inside  of.  and  separated  from,  the  apex  of  the 
external  face.  On  the  inner  and  posterior  faces  of  this  pi-emolar,  there 
is  a  strong  basal  ridge,  which  is  nearly  or  quite  obsolete  on  the  anterior 
face. 


Fl&UEE  53. — Upper  molar  series  of  Tinoceras  stenops,  Marsh  (No.  1567) ;  seen  from  below. 
FiGtTRE  54. — Lower  molar  series  of  same  specimen ;  seen  from  above,     in.  molar ;  pm.  premolar. 

The  figures  are  three-fourths  natural  .size. 


The  second  upper  premolar  in  this  series  is  much  larger  than  the 
one  last  described.  The  crown  is  sub-cordate  in  outline,  the  apex  pointing 
inward,  and  somewhat  backward.  The  essential  features  of  the  crown 
consist  of  two  transverse  ridges,  which  meet  internally,  forming  a 
V-shaped  figure.  This  is  the  characteristic  type  of  the  upper  molar 
series  in  the  Dinocerata.  The  anterior  transverse  ridge  of  this  tooth  has 
its  external  extremity  somewhat  curved  backward.  This  premolar  has  a 
well  marked  basal  ridge,  entirely  surrounding  it,  although  somewhat  thin 
near  the  middle  of  the  anterior  border. 


48  DINOCERATA. 

The  last  upper  premolar  is  very  similar  to  the  one  just  described. 
Its  crown  is  somewhat  more  triangular  in  outline,  and  the  crests  of  the 
transverse  ridges  are  straighter.  The  basal  ridge  is  continued  and  well 
developed. 

The    Upper    Molars. 

The  first  true  molar  is  much  like  the  last  premolar  in  general  form. 
It  shows  by  its  greater  wear  that  it  made  its  appearance  before  the  last 
premolar,  and  in  this  way  its  true  position  in  the  series  is  indicated.  The 
anterior  transverse  crest  in  this  tooth  is  considerably  larger  than  the 
posterior  crest,  and  the  valley  between  them  is  much  wider  than  in  the 
premolars.  Behind  the  posterior  crest,  moreover,  there  is,  on  the  inner 
postei'ior  angle  of  the  crown,  a  distinct  tubercle.  This  is  seen  in  all  of  the 
true  molars  in  Dinoceras,  and  will  distinguish  them,  at  once,  from  pre- 
molars of  similar  general  form.  The  basal  ridge  of  this  first  molar  is  well 
developed,  except  on  the  outer  side,  opposite  the  outlet  of  the  transverse 
valley. 

The  second,  or  penultimate,  upper  molar  is  much  larger  than  the  first, 
but  similar  in  general  form.  The  transverse  and  antero-posterior 
diameters  of  the  crown  are  nearly  equal,  the  fonner  being  somewhat 
greater.  The  basal  ridge  is  well  developed  on  the  posterior  side  of  the 
crown,  and  distinct  on  the  internal  and  anterior  faces,  but  is  obsolete  on 
the  external  face,  near  the  middle. 

The  last  upper  molar  is  much  the  largest  of  the  series,  and  the 
transverse  diameter  of  the  crown  is  considerably  greater  than  the 
antero-posterior  diameter.  The  anterior  crest  is  larger  than  the  posterior, 
■and  considerably  curved,  with  tlie  convexity  in  front.  The  posterior  crest 
is  nearly  straight,  but  does  not  join  the  anterior  crest  closely  at  its  inner 
extremity,  the  two  forming  a  U-shaped  figure.  Back  of  the  crest,  on  the 
posterior,  internal  border,  there  are  two  distinct  tubercles  in  this  specimen, 
as  shown  in  Plate  VII,  figure  2.  The  basal  ridge  is  continuous,  except 
between  the  outer  margin  of  the  lateral  crests,  where  it  is  lost  in  the 
depression  on  this  part  of  the  crown. 


THE   TEETH.  49 

In  Dinoceras  lucare  (number  1038),  the  upper  molar  teeth  agree  with 
those  already  described,  in  their  main  characters,  but  as  this  individual 
was  considerably  older  than  the  type  of  Dinoceras  mirabile,  the  teeth 
show  a  greater  degree  of  wear,  as  represented  in  Plate  IX,  figure  2. 

In  the  genus  Tinoceras,  the  upper  molar  series  is  essentially  the  same 
in  position  and  structure  as  in  Dinoceras. 

In  Tinoceras  ingens  (number  1041,  Plate  XVIII,  figure  2),  the  upper 
series  of  molar  teeth  is  shown,  with  a  still  greater  degree  of  wear  than  in 
those  above  described.  In  figure  53,  page  47,  the  upper  molar  series 
of  Tinoceras  stenops  is  represented. 


The  Lower  Premolars. 

In  each  ramus  of  the  lower  jaw  of  Dinoceras,  there  is  a  close  series  of 
six  teeth,  three  of  which  are  premolars,  and  three  true  molars.  These  are 
all  inserted  each  by  two  roots.  This  is  also  true  of  the  genus  Tinoceras. 
In  these  two  genera,  so  far  as  known,  there  is  no  indication  of  any 
premolar  in  front  of  this  series. 

The  first  premolar  of  the  typical  ungulate  dentition  has  not  been 
detected  in  any  specimen,  young  or  old,  of  these  genera.  In  the  lower 
jaw  of  Uintatherium,  as  this  genus  is  here  defined,  there  were  four 
premolars.  The  first  lower  pi-emolar  is  here  present,  situated  somewhat 
in  front  of  the  others,  and  but  little  separated  from  the  lower  canine.  It 
was  a  small  tooth,  inserted  by  two  roots,  and  in  all  probabilit}^  had  no 
predecessor.  The  position  of  this  tooth  is  shown  in  figures  41  and  42  on 
page  39. 

The  second  lower  premolar,  the  first  of  the  series  in  Dinoceras,  was 
inserted  by  two  roots.  Its  crown  consists  of  a  large  anterior  lobe,  and  a 
small  posterior  one.  There  is  a  distinct  basal  ridge  on  the  external 
surface,  which  curves  around  upon  the  anterior  and  posterior  faces,  but 
is  wanting  on  the  inner  surface. 
7 


50  DINOCEKATA. 

The  second  premolar  of  this  series,  representing  the  third  premolar, 
is  considerably  larger  than  the  one  in  front  of  it,  and  its  crown  is  less 
compressed  ti'ansversely.  The  anterior  and  posterior  lobes  of  the  crown, 
especially  the  former,  are  here  elongated  in  the  transverse  ridges, 
approximating  to  the  V-shaped  figure  in  the  corresponding  upper 
premolars.  The  basal  ridge  is  here  on  the  external  face,  and  curves 
around  behind,  so  as  to  enclose  the  posterior  tubercle. 

The  last  lower  premolar  is  very  similar  in  form  and  size  to  the  one 
before  it,  but  is  somewhat  larger.     The  basal  ridge  has  a  similar  position. 

The  Lower  Molars. 

The  first  true  lower  molar  is  smaller  than  the  last  premolar,  but  is 
similar  in  the  general  form  and  composition  of  its  crown.  It  shows  a 
greater  degree  of  wear  than  the  tooth  in  front  of  it,  thus  indicating  that  it 
appeared  earlier,  and  is  the  first  of  the  true  molai-  series.  The  inner  end 
of  the  anterior  lobe,  or  crest,  has  its  summit  divided  by  a  distinct  notch, 
a  trace  of  which  was  seen  in  the  corresponding  part  of  the  last  lower 
premolar.  Tlie  basal  ridge  is  distinct  on  the  outer  face,  and  likewise 
curves  around  behind  the  posterior  lobe. 

The  second,  or  penultimate,  lower  molar  is  much  larger  than  the  first, 
and  has  the  transverse  ridges  much  more  strongly  developed.  The 
anterior  one  is  considerably  elevated,  and  the  two  do  not  meet  closely 
on  the  inner  side.  The  basal  i-idge  is  here  distinct  on  the  outer  surface, 
and  swells  in  front  into  a  distinct  ridge,  and  behind  into  a  broader  crest, 
or  heel. 

The  last  lower  molar  in  JDinoceras  is  much  the  largest  of  the  series. 
The  anterior  crest  is  nearly  straight  transversely.  The  posterior  crest  is 
inclined  inward  and  forward,  the  two  meeting  on  the  inner  face,  forming  a 
distinct  V-shaped  pattern.  The  posterior  lobe,  or  heel,  is  here  largely 
developed,  and  more  distinctly  sei^arated  by  a  deep  valley,  from  the  two 
crests  just  described. 

The  position  and  general  form  of  the  lower  molar  teeth  in  Dinoceras 
laticeps  is  sliown  in  Plates  XII  and  XIII. 


THE   TEETH.  51 

The  corresponding  teeth  in  the  genus  Tinoceras  are  well  shown  in 
Plate  XIX.  The  posterior  transverse  crest  of  the  penultimate  and  last 
lower  molar  have  here  a  distinct  tubercle  at  their  inner  extremity,  at  tlie 
apex  of  the  typical  V-shaped  pattern.  This  is  shown  esjDecially  in  figure 
2  of  Plate  XIX.  In  figure  54,  on  page  47,  the  lower  molar  series  of 
Tinoceras  stenojjs  is  represented. 

All  of  the  incisors,  canines,  and  premolars  in  Dinoceras  and  Tinoceras 
appear  to  have  been  preceded  by  a  series  of  temporary  teeth.  The 
incisors,  and  lower  canines  sometimes  made  their  appearance  before 
their  small  predecessors  had  disappeared.  In  one  specimen,  represented 
in  figures  39  and  40,  page  38,  these  immature  teeth  are  seen  in  place  in 
small  cavities  in  the  sides  of  the  alveoles  of  the  permanent  dentition. 

The  lower  incisors  and  their  accompanying  canines  are  usually  more 
or  less  worn.  This  is  due  mainly  to  the  food  consumed,  and  in  part  to  the 
attrition  of  the  upper  canines,  and,  perhaps,  also  to  a  heavy,  coarse,  upper 
lip.  The  premaxillaries,  being  edentulous,  probably  supported  a  pad,  as 
in  ruminants. 

The  upper  canines  show  distinct  traces  of  wear  on  their  inner  surface 
near  the  base,  and,  also  below,  near  the  apex  of  the  crown.  This  wear  is 
probably  due  to  the  action  of  the  agencies  just  described. 

A  more  difficult  problem  is  presented  by  the  worn  surface 
sometimes  seen  on  the  outer  face  of  these  tusks,  somewhat  below  the 
insertion  in  the  jaw,  as  shown  in  figure  61,  page  45.  This  is  probably 
due  to  the   wearing  action  of  a  heavy    upper   lip. 

The  molar  teeth  in  Dinocerata  appear  to  resemble  more  closely  the 
corresponding  teeth  in  the  genus  Coryiihodon  than  those  of  any  other 
animal.  The  general  dentition,  however,  is  quite  distinct.-  Coryphodon 
has  well  developed  upper  incisors,  and  a  medium-sized  upper  canine,  thus 
differing  widely  in  these  features  from  the  Dinocerata.  The  position  and 
size  of  these  teeth  in  Coryphodon  are  shown  in  figure  66,  page  63.  The 
upper  and  lower  molar  series  are  shown  in  figures  55  and  56,  page  52. 


52 


DINOCERATA. 


Figure  55.— TJoper  molar  series  of  Corypkodon  fiamatus,  Marsh  (No.  1.334);    seen  from  below. 
FiauEE  56. — Lower  molar  series  of  same  speeiraeu  ;    seen  from  above. 

Both  figures  are  one-half  natural  size. 


CHAPTER    lY. 


THE    BRAIN. 
(Plate  VI.) 


The  brain  of  the  Dinocerata  is  one  of  the  most  peculiar  features  of  the 
group.  It  is  especially  remarkable  for  its  diminutive  size.  It  was 
proportionally  smaller  than  in  any  other  known  mammal,  recent  or 
fossil,  and  even  less  than  in  some  reptiles.  It  was,  indeed,  the  most 
reptilian  brain  in  any  known  mammal.  In  Dinoceras  mirabile  (number 
1036),  the  entire  brain  was  actually  so  diminutive  that  it  could  apparently 
have  been  drawn  through  the  neural  canal  of  all  the  presacral  vertebrae, 
certainly  through  the  cervicals  and  the  lumbars. 

The  size  of  the  entire  brain  in  Dinoceras,  as  compared  with  that  of  the 
cranium,  is  shown  in  the  accompanying  cuts,  figures  7  and  8,  page  15,  and 
figures  57  and  58,  page  54.  The  size  of  the  brain-cavity,  and  its  position 
in  the  skull  in  Tinoceras,  also,  is  represented  in  figure  9,  page  16,  and 
figure  67,  page  63. 

The  most  striking  feature  in  the  brain-cavity  itself,  is  the  relatively 
small  size  of  the  cerebral  fossa,  tliis  being  but  little  larger  than  the 
cerebellar  portion.  This  is  well  shown  in  Plate  VI,  the  figures  of  which 
are  drawn  from  the  cast  of  the  brain-cavity  of  Dinoceras  mirabile,  the  type 
of  the  genus. 


54 


DINOCERATA. 


The  cerebral  hemispheres  did  not  extend  at  all  over  the  cerebellum  or 
the  olfactory  lobes.  The  latter  were  large,  and  continued  well  forward. 
The  hemispheres  were  probabl}-  convoluted,  and  the  sylvian  fissure 
appears  to  be  distinctly  marked. 


ElG.  58. 


Figure  57. — Skull  of  Dinoceras  bticeps,  Marsh  (No.  1039);  mnle ;  with  brain-cast  in  position. 
PieUEB  58. — SkuW  of  Dinoceras  latice2JS  {So.  1202);  femule;  with  brain-east  in  position. 

/.  frontal  bone  ;  ;n.  maxillary  bone  ;  m'.  maxillary  protulierMUce;  »i.  nasal  bone  ;  ■«'.  nasal  protuberance  ; 

p.  parietal  bone  ;  p'.  parietal  protuberance  ;  s.  supraoccipital  crest. 

Both  figures  are  one-eighth  natural  size. 


The  cerebellar  fossa  is  but  little  larger,  transversely,  than  the 
medullar  canal,  and  has  lateral  cavities,  which  were  probably  occupied 
by  flocculi.  There  was  a  rudimentary  tentorial  ridge.  The  pituitary 
fossa  is  nearly  round,  and  of  moderate  depth.  There  are  no  clinoid 
processes. 


THE   BRAIN. 


55 


The  Cranial  Nerves. 

The  nerves  passing  off  from  the  brain  were  large,  and  can  be  made 
out  with  reasonable  certaint}'.  The  olfactory  lobes  were  separated  in 
front  by  an  osseous  septum,  the  position  of  which  is  shown  distinctly  in 
Plate  VI,  figure  2 

Fig.  59. 


^ 


^ 


Figure  59. — Cast  of  brain-cavity  of  K»oceras  «(/ens,  Marsh  (N"o.  1011);     \'\-    .i'W 
PIG0EE  (10. — Tlie  same  ;  superior  view. 

c.  cerebral  hemispheres ;  c6.  cerebellum;  /  flocculus  ;   7n.  medulla  ;  o?.  olfactory  lobes ;   ojj.  optic  nervt 

V.  fifth  uerve;   XII.  twelfth  nerve. 

Both  figures  are  three-fourths  natural  size. 


5a  DINOCERATA. 

The  cribriform  plate,  bounding  these  lobes  in  front,  is  thin  and  easily 
displaced,  but  its  position  in  the  specimen  is  shown  approximately  by  the 
extremity  of  the  olfactory  lobes  represented  in  Plate  VI.  In  front  of  this 
plate  the  olfactory  nerves  were  spread  out  in  a  large  cavity,  which  is 
represented  in  figures  30  and  31,  page  29.  The  nasal  canals  extend 
forward  from  this  cavity  to  the  external  nares,  as  indicated  in  the  same 
figures.  In  these  canals  there  were  thin,  well  developed,  ethmo-turbinal 
bones,  which  were  easily  displaced,  and  broken  up.  The  presence  of 
these  bones  is  strong  evidence  that  there  was  no  proboscis. 

The  optic  nerves,  or  second  pair,  were  well  developed.  Their 
position,  size,  and  place  of  exit,  are  shown  in  Plate  VI,  figure  3,  op. 

The  fifth  pair  of  nerves,  or  tri-geminals,  were  very  large,  and  were 
given  off  on  either  side,  behind  the  optics,  and  opposite  the  depression  for 
the  pituitary  body,  as  shown  in  Plate  VI,  figure  3,  v. 

The  sixth  pair  of  nerves  passed  off  immediately  behind  and  below  the 
last  pair.  Their  position  and  relative  size  are  shown  in  Plate  VI,  figure 
3,  /  The  twelfth  pair,  or  hj^poglossal  nerves,  ^jassing  off  through  the 
condylar  foramina,  were  large,  and  their  position  is  given  in  Plate  VI, 
figure  3,  XII,  and  cf.  The  position  and  exit  of  the  other  nerves  sent  off 
from  the  brain  cannot  be  determined  with  certainty. 

In  the  genus  Tinoceras,  the  brain  was  similar  in  its  general  characters 
to  that  of  JDinoceras,  but  appears  to  have  been  somewhat  more  highly 
developed,  as  shown  in  figures  59  and  60,  page  55.  The  hemispheres 
were  more  elongate,  and  the  olfactory  lobes  relatively  smaller.  The 
cavities  for  the  flocculi  were  quite  large,  and  directed  well  forward. 
The  twelfth  pair  of  nerves  were  largely  developed. 

In  UintatJierium,  the  brain  of  the  type  specimen  was  nearly,  or  quite, 
as  small  as  in  Dinoceras.  The  hemispheres  were  short,  and  moderately 
expanded  transversely.  The  olfactory  lobes  were  separated  by  a  wide 
septum,  and  were  much  more  divergent  than  in  Dinoceras  or  Tinoceras. 
These  characters  are  shown  in  figures  61  and  62,  page  57,  which  are  of 
the  same  relative  size  as  the  ficfures  in  Plate  VI. 


THE  BRAIN. 


57 


Figure  61. — Cast  of  brain-cavity  of  Uintaiherium  rohustwn,  Loidy ;  type  specimen,  lateral  vien*. 
Figure  62. — The  same ;   superior  view. 

c.  cerebral  hemispheres;  ch.  cerebellum;  /.  Hooeulus;  7Ji.  medulla ;  ol.  olfactory  lobes;  op.  optic  nerves; 

Y.  tifth  nerve  ;  XII.  twelfth  nerve. 

Both  figures  are  three-fourths  natural  size. 


Brain  Growth. 


The  Dinocerata  are,  by  far,  the  largest  of  all  known  Eocene  land 
animals,  and  that  they  have,  also,  a  very  diminutive  brain  is  a  noteworthy 
fact,  which  attracted  the  autlior's  attention  soon  after  their  discovery. 


58  DINOCERATA. 

The  comparison  of  the  brain  in  this  group  with  that  of  other  mammals 
from  the  same  formation  soon  showed  that  the  D'mocerata,  although  most 
remarkable  in  this  respect,  were  not  alone  in  diminutive  capacity  of  brain 
power.  A  more  extended  comparison  led  to  the  fact  that  all  of  the 
early  Tertiary  mammals  had  very  small  brains,  and  in  many  of  them 
the  brain  was  of  a  low,  almost  reptilian,  tyj^e.  As  the  comparison 
was  extended  to  include  the  mammals  from  the  higher  divisions  of  the 
Eocene,  and  from  the  Miocene,  the  same  fact  became  more  apparent,  but  a 
gradual  increase  in  size  and  quality  of  the  brain  soon  became  evident  in 
extending  the  investigation  to  the  animals  of  more  recent  geological  ag-e. 
In  bringing  into  the  investigation  the  mammals  from  the  Pliocene  and 
Quaternary,  tlie  improvement  in  brain  power  became  still  more  apparent, 
and  the  outline  of  a  general  law  of  brain  growth  was  soon  determined. 

In  tracing  thus  the  different  groups  of  manimals,  each  from  the  early 
Tertiary  to  the  present  time,  it  was  found  that  in  every  series  where  the 
material  was  sufficient  to  make  a  fair  comparison,  the  brain-growth  had 
been  constant,  and  followed  the  same  law. 

The  results  of  this  investigation  were  embodied  by  the  author  in  a 
general  law  of  brain-growth  in  the  extinct  mammals  tkroughout  Tertiary 
time.     This  law,  briefly  stated,  was  as  follows : 

1.  All  Tertiary  mammals  had  small  brains. 

2.  There  was  a  gradual  increase  in  the  size  of  the  brain  during  this 
period. 

3.  This  inci'ease  was  confined  mainly  to  the  cerebral  hemispheres,  or 
higher  portion  of  the  brain. 

4.  In  some  groups,  the  convolutions  of  the  brain  have  gradually 
become  more  complex. 

5.  In  some,  the  cerebellum  and  the  olfactory  lobes  have  even 
diminished  in   size. 

6.  There  is  some  evidence  that  the  same  general  law  of  brain 
growth  holds  good  for  Birds  and  Reptiles  from  the  Cretaceous  to  the 
present  time.^ 

^American  Journal  of  Science  and  Arts,  Vol.  VIII,  p.  66,  July,  1874;  and  Vol.  XII, 
p.  61,  July,  1876;  see  also  the  author's  Monograph  on  the  ODOifTOENiTHES,  p.  10,  4to, 
Washington,  1880. 


THE   BRAIN.  59 

The  author  has  since  continued  this  line  of  investigation,  and  has 
ascertained  that  the  same  general  law  of  brain  growth  is  true  for  Birds 
and  Reptiles  from  the  Jurassic  to  the  present  time. 

To  this  general  law  of  brain  growth  two  additions  may  now  be 
made,  which  briefly  stated  are  as  follows : 

(1.)  The  brain  of  a  mammal  belonging  to  a  vigorous  race,  fitted  for  a 
long  survival,  is  larger  than  the  average  brain,  of  that  period,  in  the  same 
group. 

(2.)  The  brain  of  a  mammal  of  a  declining  race  is  smaller  than  the 
average  of  its  cotem^^oraries  of  the  same  group. 

An  example  of  the  first  of  these  statements  is  seen  in  figure  70, 
page  64,  representing  the  genus  Colonoceras,  one  of  the  Eocene  ancestors 
of  the  Rhinoceros.  The  second  case  is  illustrated  by  figure  82,  page  67, 
of  the  Hippopotamus,  evidently  one  of  the  last  members  of  a  long  line. 
A  study  of  a  larger  number  of  extinct  and  recent  specimens  will  make 
these  conclusions  more  apparent. 

The  results  of  this  study  of  the  whole  subject  of  brain  growth,  the 
author  intends  to  bring  together  in  a  separate  memoir.  Some  of  the 
principal  facts,  however,  may  be  appropriately  presented  in  the  present 
volume  in  connection  with  the  brain  characters  of  the  Dinocerata,  which 
naturally  form  the  beginning  of  one  series  in  the  investigation. 

In  any  comparison  of  the  size  of  the  brain  in  different  animals, 
whether  in  the  same  group  or  in  others  widely  diff"erent,  it  is  important 
to  bear  in  mind  that : 

1.  The  brain  of  small  animals  is  proportionally  larger  in  bulk  than 
that  of  large  animals. 

2.  The  brain  of  young  animals  is  proportionally  larger  than  in  those 
fully  adult. 

In  a  general  comparison  of  brain  growth  of  mammals,  the  first  of 
these  facts  can  have  only  a  limited  efi'ect,  which  would  not  change, 
essentially,  the  general  results.  The  effects  of  the  second  fact  may  be 
readily  eliminated  by  confining  the  comparison  to  adult  animals. 


60  DINOCERATA. 

In  this  comparison,  moreover,  of  the  extinct  forms  with  those  of  more 
modern  time,  including  recent  mammals,  it  may  be  taken  for  granted  that 
the  brain-cavity  of  the  extinct  forms,  as  well  as  of  those  now  living,  was 
entirely  filled  by  the  brain ;  since,  with  a  possible  single  exception,  no 
mammal  is  known  in  which  this  is  not  the  case. 

In  comparing  the  size  of  the  brain  in  mammals  with  that  of  reptiles 
and  fishes,  an  important  point  to  be  borne  in  mind  would  be  the  fact,  that 
in  the  two  latter  classes  the  brain-cavity  is  not  always  entirely  filled  by 
the  brain.  The  present  comparison  deals  with  mammals  alone,  and  this 
restriction  is  here  of  no  importance. 

The  fact  that  among  existing  mammals  there  are  some  anomalous 
features  in  the  size  of  the  brain  in  allied  groups  has  not  been  forgotten, 
but  such  instances,  even  if  they  occurred  among  extinct  mammals,  would 
not  materially  affect  the  general  comparison  here  proposed. 

In  the  following  pages  a  series  of  figures  is  given,  showing  the 
comparative  size  of  the  brain,  and  its  position  in  the  skull  in  a  number 
of  the  larger  ungulate  mammals,  recent  and  extinct.  To  make  the 
compai'ison  a  fair  one,  the  skulls  are  all  drawn  of  the  same  absolute 
size,  thus  showing,  at  once,  the  relative  proportion  of  the  brain  in  each. 
The  skulls  are  placed  horizontally,  the  plane  of  the  molar  teeth  being  as  a 
rule  taken  as  a  base.  In  the  case  of  the  four  artiodactyls,  figures  80  to 
83,  page  67,  this  position  has  been  somewhat  changed,  as,  in  this  group 
of  ungulates,  the  brain  is  more  or  less  inclined  backward  in  the  skull.  In 
these  cases,  the  skull  is  represented  as  somewhat  inclined  forward,  thus 
raising  the  posterior  part  of  the  brain.  The  angle  of  inclination  of  the 
face  and  of  the  brain,  is  made  equal,  thus  giving  to  both  the  best  position 
for  comparison,  and  not  materially  affecting  it  for  the  present  purpose. 

A  striking  illustration  of  the  development  of  the  brain  from  the  early 
Tertiary  to  the  present  time  may  be  seen  in  figures  63-65,  page  61,  where 
is  shown,  first,  the  skull  of  Dinoceras,  the  largest  land  mammal  of  the 
Eocene,  with  the  brain  in  position  ;  second,  the  skull  of  the  gigantic 
Miocene  Brontotheriuni,  with  the  brain  also  in  position;  and  third,  the  skull  of 
the  recent  horse.     Other  comparisons,  equally  striking,  can  readily  be  made. 


THE   BKAIN. 


61 


Fig.  65. 


FiGUHB  63. — Outline  of  skull  of  Dinoceras  mirabile.  Marsh;   with  cast  of  brain-cavity  in  position-   about  one. 

cifcljth  natural  size.      Eocene. 
Figure  et — Outline  of  skull  of  Brontotherium  ingens,  Marsh;   with  cast  of  brain-cavity  in  position;  one-tenth 

natural  size.      Miocene. 
Figure  65. — Outline  of  skull  of  horse,  Equns  caballus,  Lini.acus;    with  cast  of  brain-cavity  in  position;    about 

one-sixth  natural  size.     Recent. 


62  DINOCEKATA. 

The  small  size  of  the  brain  in  early  Tertiary  mammals  will  be 
indicated  by  an  examination  of  the  Binocerata  skulls,  with  the  brain  in 
position,  shown  in  figures  57  and  58,  j)age  54.  This  is  further  shown  by 
figure  66,  jjage  63,  which  represents  the  skull  and  brain  of  Coryphodon, 
the  largest  mammal  in  the  lower  Eocene,  from  beds  of  earlier  age  than 
those  containing  the  Bhiocerafa,  as  shown  in  the  section,  figure  2,  page  7. 

The  size  of  the  brain  in  the  middle  Eocene  genera  Pdteosyops, 
Lymnoliyus,  Colonoceras,  and  Hyracliyus  are  shown  in  figures  68  to  71, 
pages  63  and  64.  Amynodon  from  the  upper  Eocene  is  represented  in 
figure  72,  page  64. 

The  larger  brain  of  the  Miocene  mammals  is  indicated  by  the  figure 
64,  page  61,  representing  the  skull  of  Brontotlierium,  which  is  found  at  the 
base  of  the  Miocene,  as  shown  in  figure  2,  page  7.  EJoiherimn  from  the 
same  horizon  is  represented  in  figure  75.  The  skull  of  Eporeodon,  with  its 
brain  in  position,  figure  73,  page  64,  also  aftbi'ds  a  good  illustration  of  a 
mammal  from  this  formation.  This  genus  is  found  in  the  middle  Miocene, 
as  shown  in  the  section,  page  7. 

The  still  more  developed  brain  of  the  Pliocene  mammals  is  seen  in 
figure  74,  page  65,  which  gives  a  view  of  the  skull  of  the  Mastodon,  with 
the  brain  in  position.  In  figure  76,  page  65,  the  skull  and  brain  of  an 
extinct  Pliocene  peccary  further  illustrates  the  same  law  of  brain-growth. 

On  comparing  these  various  figures  with  those  representing  the  brains 
and  skulls  of  the  existing  Ungulates,  as  shown  by  the  succession  in  figures 
77-83,  on  pages  66-67,  the  reader  will  have  before  him  a  series  of  facts 
which  illustrate  the  laws  of  brain-growth  given  on  page  58.  The 
comparison,  here  confined  to  the  representative  ungulate  mammals,  might 
easily  be  extended  much  farther,  but  would  not  come  within  the  scope 
of  the  present  volume. 

The  author  has  made  similar  comparisons  in  other  groups  of  mammals, 
including  those  that  can  be  followed  from  the  early  Tertiary  to  the  present 
time,  and  the  results  are  uniformly  the  same.  These  results  the  author 
hopes  to  present  fully  elsewhere  at  no  distant  day. 


THE  BRAIN. 


63 


Fig.  66. 


Fie.  68. 


FionHE  66. —  Coryphodon  hamatus,  Marsh.     Eocene. 
FiSUSE  68. — PaliKOsyops  laticeps.  Marsh.     Eocene. 


Figure  6'?. — Tinoceras  pugnax,  Marsh.     Eocene. 
Figure  69. — Limnohyus  robastus,  Marsh.     Eocene. 


64 


DINOCERATA. 


FiGUBB  'JO. —  Colonoceras  agreslis,  Harsh.     Kocene. 
Figure  l-i.—Syrachyus  Bairdianus,  ihrsh.     Eocene. 


FiGUEE  ll.—Amynodon  advenus.  Marsh.     F.ocene, 
Figure  r?,.SporeodonsociaKs,'i>\a's:&h-     Miocene. 


THE  BRAIN. 

Fig.  14. 


65 


Figure  74. — Mastodon  Americanus,  Cuvier.     Pliocene. 
Fig.  75.  Fig.  76. 


Figure  75. — Elothermm  crassum,  Marsh.     MioceDe.      Figure  76. — Platygonus  com.prcssus,  LeOonte.     Plipcene. 
9 


66 


DINOCERATA. 

Fig.  11. 


Figure  11. — Elejphas  Indicus,  Linnteiis. 


Figure  IS. — Tupirvs  terrestris,  Linn:eiis. 


Figure  l^.—Ii/uuoccros  Swnalrensis,  CuviBr._ 


THK   BRAIN. 


67 


Figure  80. — Auchenia  vicugna,  Molina. 
PiGOHB  82. — Bippopoiamus  amphibius,  Linnffiis, 


FrSUEE  81. —  Cervus  Virginianus,  Boddaut. 
Figure  83. — Dicotyles  iorquatus,  Cuvier, 


CHAPTER     y. 

THE   CERVICAL   VERTEBRAE. 
(Plates  XX,  XXI,  XXII,  LV,  and  LVI.) 

The  cervical  vertebrse  of  thd  Binocerata,  in  tlieir  main  characters, 
resemble  those  of  tlie  Proboscidians.  The  atlas  and  axis  are  somewhat 
similar  to  those  of  the  elej^hant.  The  rest  of  the  cervicals  are  proportionally 
longer.  The  entire  neck  was  abont  one-third  longer  than  in  the  elephant, 
thus  rendering  a  proboscis  unnecessary,  as  the  head  could  readily  reach 
the  ground. 

All  the  presacral  vertebrae,  behind  the  atlas  and  axis,  have  the 
articular  faces  of  the  centra  nearly  flat,  as  in  the  typical  Proboscidians. 
In  other  respects,  they  present  no  strongly  marked  characters  of 
importance. 

The    Atlas. 

(Plate  XX ;    and  woodcuts  84,  85,  and  86,  below.) 

The  atlas  in  the  Binocerata  is  a  massive  bone,  presenting  the  ordinary 
articular  faces  of  this  vertebra.  The  anterior  pair  of  these,  for  the 
reception  of  the  occipital  condyles,  are  well  separated  above  and  below. 
The  three  posterior  faces,  for  articulation  with  the  second  vertebra,  or  axis, 
are  also  widely  separated  from  each  other.  All  these  three  faces  are 
sub-circular  in   outline,  and  the    lateral    ones  are   somewhat  emarginate 


70  DINOCEKATA. 

along  the  inner  side.  The  median  facet,  for  articulation  with  the  odontoid 
process,  is  flattened  in  front,  or  slightly  convex  in  antero-posterior 
direction,  and  extends  longitudinally  over  the  greater  part  of  the  inferior 
arch  of  the  atlas.  Its  boundaries  are  well  marked  on  all  sides,  as  are 
also  those  of  the  lateral  faces.  Hence  the  articulation  between  the  atlas 
and  axis  admitted  but  little  rotary  motion  to  the  head. 

The  spine  of  the  atlas  is  not  well  marked,  although  the  superior  arch 
is  massive,  and  its  anterior  surface  is  rough  and  tuberculated.  This  arch 
is  pierced  on  each  side  anteriorly  by  a  foramen  (figure  84,  d),  the  inner 
Ojjening  of  which  is  just  above  the  inner  and  upj)er  angle  of  the  condylar 
articular  surface.  Externally,  this  foramen  is  connected  bv  a  more  or  less 
evident  groove  with  one  piercing  the  transvei'se  ])rocess  lengthwise.  This 
groove  runs  vertically  down  the  side  of  the  atlas,  and  through  a  deep  notch 
in  the  anterior  margin  of  the  transverse  process.  In  the  tapir,  this  groove 
passes  through  a  foramen,  instead  of  a  notch  in  tlie  anterior  part  of  the 
transverse  process.  A  similar  arrangement  is  seen  in  the  horse,  ox,  sheep, 
camel,  and  in  various  other  Ungulates. 

The  transverse  processes  of  the  atlas  are  short,  and  strong.  They  are 
moderately  flattened,  thicker  and  stouter  behind  than  before,  and  placed 
obliquely,  so  as  to  slant  strongly  downward  and  backward.  Anteriorly, 
the  outer  margin  runs  rapidly  down  to  the  lateral  arch  of  the  atlas,  but  is 
separated  from  it  at  the  base  of  the  process  by  the  deep  notch,  mentioned 
above.  Posteriorly,  they  are  thickened  and  rugose.  The  base  of  each 
lateral  process  is  perforated  by  a  foramen,  directed  somewhat  downward, 
and  forward.  The  under  surface  of  the  atlas  (figure  86)  is  smooth  and 
even,  with  no  rugosity  to  mark  the  median  line. 

The  atlas  of  Dinoceras  mirahih  is  shown  in  Plate  XX,  and  that  of 
Tinoceras  grande,  in  the  woodcuts  below,  figures  84,  85,  and  86.  The 
position  of  the  atlas,  with  reference  to  the  skull,  is  represented  in  the 
restorations  in  Plates  LV  and  LVI. 


THE   CERVICAL   VERTEBRA. 


71 


Fig.  86. 


FiGURR  84. — Albs  of  TmOLCiat,  giaiicL,  Mu^h  (No   ]040);  front  view. 
Figure  8.5. — The  same  vei tebia ,  back  view 
FiGDEK  Bfi. — The  same  vertebra ;  bottom  view. 

a.  face  for  axis;  6.  fare  Air  odontoid  process  of  a.xis;  c.  face  for  occipital  condyle  of  skull;  d.  foramen 

in  neural  arch  for  spinal  nerve;  nc.  neural  canal. 

All  the  fignres  are  one-fourtli  natural  size. 

The   following-  measfirements   give   the   princijial  dimensions   of  the 
atlas  in  one  specimen  of  Dlnoceras  : 


Measurements  of  Atlas.     {Dhiooeras  miraUe,  No.   12.51.) 

m. 

Greatest  transverse  diameter  of  atlas, ._ .26.5 

Greatest  vertical  diameter  of  atlas, . .  - .  1 4  _' 

Transverse  diameter  of  neural  canal, , .090 

Vertical  diameter  of  neural  canal, 080 

Antero-posterior  diameter  of  superior  arch, - .067 

Vertical  diameter  of  superior  arcli, .034 

Antero-posterior  diameter  of  inferior  arch,   __ .149 

Diameters  of  faces  for  occipital  condyles,  -' .0'72-.05'2 

Distance  between  faces  for  occipital  condyles,  above, -     .080 

Distance  between  faces  for  occipital  condyles,  below, .  - .  . .058 

Diameters  of  face  for  odontoid  process, —  - 04.3-.035 

Diameters  of  lateral  faces  for  axis, 063-.056 

Distance  between  lateral  faces  for  axis, .065 


72  DINOCERATA. 

The  Axis.     (Plate  XXI.) 

The  axis  in  Binoceras  mirahile  (number  1036)  is  robust,  and 
proportionally  shorter  than  the  corresponding  vert3bra  in  the  tapir.  The 
centrum  is  moderately  flattened  below,  but  not  excavated  as  in  the  tapir, 
and  presents,  medially,  a  tuberculation  at  the  union  of  its  centrum  with 
that  of  the  first  vertebra.  The  odontoid  process  is  distinctly  conical,  and 
not  at  all  excavated  above.  Its  perpendicular  diameter,  moreover,  exceeds 
its  transverse.  It  is  pointed  in  front,  and  bears,  on  its  imder  surface,  a 
saddle-shaped  articular  face  for  union  with  the  atlas.  This  surface  is  not 
confluent  with  the  lateral  surfaces,  as  in  the  elephant,  tapir,  and  most 
Ungulates,  but  is  perfectly  distinct,  as  in  the  kangaroo,  and  in  man.  The 
lateral  articular  faces  are  moderately  convex  in  both  directions,  and  have 
their  longest  diameter  nearly  ti-ansverse. 

The  neviral  arch  is  massive,  and  its  lateral  walls  are  not  pierced  by 
foramina,  agreeing,  in  that  respect,  with  those  of  the  kangaroo.  On  the 
lateral  surfaces  of  the  centrum,  the  vertebrarterial,  or  lateral,  foramen  was 
present,  and  circumscribed  by  bone.  Its  upper  wall  was  much  weaker 
than  the  lower,  instead  of  subequal,  as  in  the  tapir.  The  neural  arch  is 
surmounted  by  a  short  and  stout  neural  spine,  low  in  front,  and  rising 
behind,  though  less  rapidly  than  in  the  tapir,  and  becoming  rather 
indistinctly  bifid  at  the  top.     The  neural  spine  is  deeply  excavated  behind. 

The  posterior  zygapophyses  are  robust,  slightly  convex,  and  look 
more  downward  than  outward,  and  only  slightly  backward.  The 
posterior  face  of  the  centrum  is  transverse,  and  broadly  oval  in  outline. 
The  floor  of  the  neural  canal  is  flattened,  and  presents  a  number  of 
vascular  foramina  leading  into  the  centrum. 

The  transverse  processes  of  this  specimen  are  imperfectly  preserved, 
but  were  evidently  pierced,  above  the  middle,  by  a  large  lateral  foramen. 
The  processes  appear  to  have  been  directed  rather  less  strongly  backward 
than  in  the  tapir. 

The  principal  dimensions  of  the  axis  in  three  specimens  of  Binoceras 
are  as  follows : 


THE   CERVICAL  VERTEBRAE.  73 

Measurements  of  Axis.     [Dinoceras  mirabile,  No.  1036.) 

m. 

Length  of  axis,  on  floor  of  neural  canal  (approximate), 150 

Length  of  odontoid  process, . .-_ .056 

Transverse  diameter  of  odontoid  process, .035 

Vertical  diameter  of  odontoid  process, -_   .052 

Transverse  diameter  of  anterior  articular  face, .068 

Vertical  diameter  of  anterior  articular  face,  .065 

Transverse  diameter  of  vertebra,  across  anterior  articular  faces, .148 

Transverse  diameter  of  neural  canal, .053 

Vertical  diameter  of  neural  canal, ._..      .042 

Transverse  diameter  of  vertebra,  across  post-zygapophyses, .122 

Transverse  diameter  of  posterior  face  of  centrum, . 093 

Vertical  diameter  of  posterior  face  of  centrum, ...    .072 

Height  of  axis,  to  top  of  neural  spine, ._ _. .       .175 

Transverse  diameter  of  neural  spine, . .. .048 

Antero-posterior  diameter  of  neural  spine, 086 

Measuremetits  of  Axis.     [Dinoceras  mirabile,  No.  1255.) 

m. 

Length  of  axis,  on  floor  of  neural  canal  (approximate), .125 

Length  of  centrum,  along  under  surface, .140 

Length  of  odontoid  process,  from  lateral  articular  faces, .045 

Transverse  diameter  of  odontoid  process, . _    .  .  .037 

Vertical  diameter  of  odontoid  process, . .038 

Transverse  diameter  of  articular  face  of  odontoid  process, .035 

Antero-posterior  diameter  of  articular  face  of  odontoid  process, .042 

Transverse  diameter  of  neural  canal, . .039 

Vertical  diameter  of  lateral  foramen, .012 

3Ieasurements  of  A.vis.     {Dinoceras  litcare.  No.   1038.) 

m. 
Total  length  of  axis, .170 

Length,  from  end  of  odontoid  process  to  end  of  neural  canal, .  1 48 

IVansverse  diameter  of  odontoid  process, .035 

Vertical  diameter  of  odontoid  process, ■ 046 

Greatest  diameter  of  anterior  articular  face, .070 

Transverse  diameter,  across  anterior  articular  faces,  . ; 142 

Antero-posterior  diameter  of  face  on  odontoid  process, .044 

Transverse  diameter  of  face  on  odontoid  process,  _ .033 

Distance  between  antero-lateral  articular  faces, .050 

Transverse  diameter  of  centrum,  behind  faces, .125 

Transverse  diameter,  across  post-zygapophyses, .115 

Transverse  diameter  of  posterior  face  of  centrum, _     .093 

Vertical  diameter  of  posterior  face  of  centrum, .080 

Diameters  of  lateral  foramen,  _ ._ _ 01 3-.020 

Diameters  of  neural  canal  (approximate), .040-050 

10  • 


74  DINOCERATA. 

The  Third  Vertebra.     (Plate  XXII,  figures  1-5.) 

The  third  cervical  of  Dinoceras  mirahile  (number  1036)  is  shown  in 
Plate  XXII,  figures  1-5.  This  vertebra,  in  the  type  specimen,  is  not  in  a 
good  state  of  preservation,  but  represents  fairly  the  main  characters  of  the 
third  cervical  in  this  genus. 

The  pre-zygapophyses  are  somewhat  concave,  to  fit  the  convex 
post-zygapophyses  of  the  axis.  The  neural  canal  is  large,  and  the  arch 
above  it  is  only  moderately  developed,  and  without  a  spine.  The  lateral, 
or  vertebrarterial,  foramen  is  oval  in  outline,  and  is  protected  by  a  strong 
transverse  process.  The  under  surface  of  the  centrum  is  marked  by  a 
median  longitudinal  keel,  as  shown  in  figures  3  and  5. 

The  third  cervical  vertebra  of  Dinoceras  mirahile  (number  1255)  is 
short,  and  the  articular  faces  of  the  centrum  are  both  somewhat  concave. 
The  anterior  face  is  slightly  less  excavated  than  the  posterior.  The  length 
of  the  centrum  is  less  than  its  vertical  diameter,  and  the  latter  is  greater 
than  the  transverse  diameter.  The  epiphyses  are  incompletely  ossified, 
and  only  imperfectly  united  to  the  centrum.  These  general  characters 
apply  also  to  the  remaining  cervical  vertebrae. 

The  principal  dimensions  of  the  third  A^ertebra  in  one  specimen  of 
Dinoceras  are  as  follows : 

3feasurenients  of  Tliird  Cervical  J^ertehnt.     (Dinoceras  mirahile,  No.  1255.) 

m. 

Length  of  floor  of  neural  canal  (approximate), . ^.-    —  .  .055 

Length  of  centrum,  along  under  surface, —  .058 

Vertical  diameter  of  posterior  epiphysis, ..-  .078 

Antero-posterior  extent  of  zygapophyses,  ._ .092 

Diameter  of  lateral  foramen  (apj)roximate), . .020 

The  Fourth  Vertebra.     (Woodcuts  87  and  88,  below.) 

The  fourth  cervical  vertebra  in  Dinoceras  resembles,  in  its  main 
characters,  the  one  last  described.  The  pre-zygapophyses  are  nearly  flat. 
The  neural  canal  is  somewhat  smaller.  The  process  to  protect  the  lateral 
foramen  is  more  strongly  developed,  and  the  under  surface  of  the  centrum 
is  without  a  distinctly  marked  keel. 


THE   CEIIVICAL   VERTEBRA.  75 

The  fourth  vertebra  in  Tinoceras  grande  is  similar,  in  its  more 
important  characters,  although  proportionally  shorter,  and  its  principal 
features  are  well  shown  in  figures  87  and  88,  below. 

Fif4    "^S 


Figure  87. — Fourth  cervical  vertebra  of  Tinoceras  grande,  Marsh  (Wo.  1040);  front  view. 
FiGORE  88. — The  same  vertebra;   side  view. 

/.  lateral  foramen;  nc.  neural  canal;  z.  anterior  zygapopliysis ;  z'.  posterior  zygapophysis. 
Both  figures  are  one-fourth  natural  size. 

The  main  dimensions  of  the  fourth   vertebra  in  one  species  each  of 
Binoceras  and  Tinoceras  are  given  below. 

Measurenients  of  Fourth  Cervical  J^erteTfra.     {Dinoceras  mirabile.  No.  1255.) 

m. 

Length  of  floor  of  neural  canal, .055 

Length  of  centrum,  along  under  surface, .054 

Transver.se  diameter  of  anterior  epiphysis, .079 

Vertical  diameter  of  anterior  epiphysis, . .075 

Transverse  diameter  of  posterior  epiphysis, .091 

Vertical  diameter  of  posterior  epiphysis, .075 

Autero-posterior  extent  of  zygapophyses, i .089 

Diameter  of  lateral  foramen, .024 

Transverse  diameter  of  neural  canal, .04.3 

Measurements  of  Fourth  Cervical  Vertebra.     {^Tinoceras  grande,  No.  1040.) 

m. 

Length  of  floor  of  neural  canal,  .-^--. .042 

Length  of  centrum,  on  under  surface  of  vertebra, .045 

Transverse  diameter  of  anterior  face, .100 

Vertical  diameter  of  anterior  face, .094 

Transverse  diameter  of  neural  canal, .055 

Vertical  diameter  of  neural  canal, .040 

Diameters  of  lateral  foramen, .025-015 


76 


DINOCERATA. 


The  Fifth  Vertkhra.     (Woodcuts  89  and  90,  below.) 

In  the  fifth  cervical  vertebra  of  Dinoceras  mirabile  (number  1255), 
the  centrum  is  nearly  round.  The  articular  faces  are  distinctly  concave, 
especially  the  posterior  one.  The  neural  canal  is  sub-triang-ular  in 
transverse  section.  The  arch  to  protect  the  lateral  foramen  is  more 
depressed  than  in  the  preceding  vertebi'a.  The  more  important  features 
of  this  vertebra  are  shown  in  figure  89,  below. 


Figure  89  — Fiflh  cervical  vertebra  ot  Iliiwceras  mirabile,  Marsh  (No.  1255);  front  view. 
FiauRE  90. — The  same  vertebra;  siJe  view. 

/.  lateral  foramen;  nc.  neural  caual;  z.  anterior  zygapoplivsis  ;  z'.  posterior  lygapophysis. 
Both  figures  are  one-fourth  natural  size. 

The  pi'incipal  measurements  of  the  fifth  vertebra  in  this  specimen  of 
Dinoceras  mirabile  are  the  following- : 


Jtfeasure/nents  of  Fifth  Cervical  Vertebra.     (Dinoceras  ■mirabile^  No.  1255.) 

m. 

Length  of  floor  of  neural  canal, .052 

Length  of  centrum,  along  under  surface, .055 

Transverse  diameter  of  neural  canal, .046 

Vertical  diameter  of  neural  canal, _. .035 

Transverse  diameter  of  anterior  epiphysis,. .079 

Vertical  diameter  of  anterior  epiphysis, , .074 

Transverse  diameter  of  posterior  epiphysis, ,._". .089 

Vertical  diameter  of  posterior  epiphysis, .080 

Antero-posterior  extent  of  zygapophyses, _.^ . .083 

Transverse  diameter,  across  pre-zygapophyses, _ .    .120 

Transverse  diameter,  across  post-zygapophyses, .123 

Diameter  of  lateral  foramen  (approximate), .020 


THE    CERVICAL   VERTEBRA. 


77 


The  Sixth  Vertebra.     (Woodcuts  91-94,  below.) 

The  sixth  cervical  vertebra  of  Dinoceras  mirabile  (number  1255)  has 
the  articular  faces  of  the  centrum  more  transverse  than  in  the  preceding- 
vertebra.  The  neural  canal  is  sub-cordate  in  outline,  and  the  transverse 
processes,  to  protect  the  lateral  foramen,  are  more  strongly  developed 
than  in  the  vertebra  last  described. 


Figure  91. — Sixth  cervical  vertebra  oil  Dinoceras  mirabile,  Marsh  (No.  1255);  bask  view. 
Figure  92. — The  same  vertebra ;  side  view. 

nc.  neuraLcanal;  z.  anterior  zygapophvsis  ;  z'.  posterior  zygapophysis. 
Both  figures  are  one-fourth  natural  size. 

Fig.  93. 


Figure  9.3.— Sixth  cervical  vertebra  o!' Dinoceras  cuneum,  Marsh  (No.  1042);  front  view. 
Figure  94  — The  same  vertebra;  side  view. 

nc.  neural  canal;  z.  anterior  zysapopliysis;  z'.  posterior  zygapophysis. 
Both  figures  are  one-fourth  natural  size. 

In  the  sixth  vertebra  of  Dinoceras  cuneum,  there  is  a  distinct  neural 
spine,  and  the  centrum  is  slightly  quadrate  in  outline,  as  shown  in  figure 
93.  The  latter  is  shorter  than  in  the  corresponding  vertebra  of  Dinoceras 
mirabile,  as  seen  by  a  comparison  of  figures  92  and  94. 

Measin-ements  of  the  sixth  cervical  vertebra  in  two  individuals  of 
Dinoceras  are  as  follows  : 


78  DINOCERATA. 

Measurements  of  Sixth  Cervical  Vertebra.     [Dinoceras  niirabile,'So.  1255.) 

m. 

Length  of  floor  of  neural  canal, .049 

Length  of  centrum,  along  under  surface, _ .055 

Transverse  diameter  of  neural  canal, — .051 

Vertical  diameter  of  anterior  epiphysis, .076 

Transverse  diameter  of  posterior  epiphysis, .088 

Vertical  diameter  of  posterior  epiphysis, .078 

Antero-posterior  extent  of  zygapophyses, .087 

Ifeasuretnents  of  Sixth  Cervical  Vertebra.     {Dinoceras  cuneutn,  No.  1042.) 

m. 

Transverse  diameter  of  centrum, .111 

Length  of  centrum,  along  under  surface, --     .053 

Transverse  diameter  of  neural  canal, .071 

Vertical  diameter  of  neural  canal  (apjjroximate), .044 

Transverse  diameter  of  anterior  face  of  centrum, .100 

Vertical  diameter  of  anterior  face  of  centrum, , .092 

Diameter  of  vertebra,  across  pre-zygapophyses  (apjDroximate), ._    —      .170 

Diameters  of  lateral  foi-amen, . .022-034 

Antero-posterior  diameter  of  pedicel, .026 

The  Seventh  Vertebra.     (Plate  XXII,  figures  6-10.) 

The  seventli  cervical  vertebra  of  Dinoceras  mirabile  (number  1255) 
has  the  anterior  face  of  the  centrum  nearly  circular.  The  posterior  face 
is  expanded  transversely,  and  its  lateral  margins  are  cut  by  the  facets  for 
the  head  of  the  first  rib.  The  neural  canal  is  distinctly  sub-cordate  in 
outline,  and  there  is  a  rudimentary  neural  spine.  The  lateral  foramen 
has  disappeared,  but  the  transverse  process  is  notched  below  for  the 
passage  of  the  vertebral  artery.  These  chai-acters  are  shown  in  Plate 
XXII,  figures  8  and  10. 

Measurements  of  Seventh  Cervical  Vertebra.     (Dinoceras  mirabile,  "So.  1255.) 

m. 

Length  of  floor  of  neural  canal, .046 

Length  of  centrum,  along  under  surface, .051 

Transverse  diameter  of  neural  canal, _     .061 

Vertical  diameter  of  neural  canal  (apjH'oximate), . .046 

Transverse  diameter  of  anterior  articular  face  (approximate), .076 

Transverse  diameter  of  posterior  articular  face  (approximate), .075 

Antero-posterior  extent  of  zygapophyses, ... .084 

Diameters  of  articulation  for  fii'st  rib, .022-. 035 

Diameter,  across  transverse  processes  (approximate), .185 


CHAPTER     YI. 


THE    DORSO-LUMBAR    VERTEBRA. 

(Plates  XXIII,  XXIV,   XXV,  XXVI,  LV  and  LVI.) 

The  trunk  vertebree  in  the  Dinocerata  are  j^i'oportionally  longer  than 
those  in  the  cervical  region.  The  articular  faces  of  the  centra  are  likewise 
nearly  flat,  the  most  of  them  being  distinctly  concave.  The  epiphyses  are 
usually  loosely  united  to  the  centra,  and  thin,  or  imperfectly  ossified,  near 
the  center.  The  number  of  trunk  vertebrae  in  Dinoceras  was  apparently 
twenty-three. 

The  First  Dorsal  Vertebra.     (Woodcuts  95-98,  below.) 

The  first  dorsal  vertebra  in  Dinoceras  mirahile  (number  1255)  has  a 
slender,  but  elevated,  neural  spine,  as  shown  in  figure  95,  below.  It  is 
distinguished  from  the  adjoining  elements  of  tlie  colunni  by  the  presence 
of  elevated  and  oblique  pre-zygapophyses,  for  articulation  ^vith  the 
last  cei'vical.  These  processes  are  much  farther  apart  than  the  post- 
zygapophyses,  and  look  obliquely  upward,  inward,  and  slightly  backward, 
while  the  latter  look  almost  directly  downward.  The  pedicels  of  this 
vertebra  stand  mostly  on  the  anterior  half  of  the  centrum.  They  are 
about  twice  as  great  in  transverse  as  in  antero-posterior  diameter,  and  are 
directed  well  outward.  The  laminae  form  a  much  greater  proportion  of 
the  neural  arch  than  in  the  tapir,  and  are  depressed  at  the  middle,  giving 
a  somewhat  triangular  outline  to  the  large  neural  canal.  The  epiphyses 
in  this  specimen  are  unossified  for  more  than  half  their  diametei-,  and 
imperfectly  united  to  the  centnmi. 


80 


DINOCERATA. 


The  transverse  processes  are  short,,  and  strongly  tnberculated  at  the 
end.  The  articular  surfaces  for  the  heads  of  the  first  and  second  ribs  are 
of  about  equal  size,  and  sub-oval  in  outline.  They  are  approximate  at 
the  sides  of  the  centrum,  being  separated  from  each  other  by  less  than 
half  their  diameter.  The  face  for  the  tubercular  articulation  of  the  first 
rib  is  of  modei'ate  size,  oval  in  outline,  concave  from  before  backward,  and 
much  less  so  transversely.  These  articulations  are  about  on  a  level  with 
the  floor  of  the  neural  canal,  instead  of  below  it,  as  in  the  tapir. 


PiGUBE  95. — First  dorsal  vertebra  of  Dinoceras  mirahile,  Marsh  (No.  1212);  front  view. 
Figure  9i;. — The  same  vertebra;  side  view. 

n,  neural  canal;    r.  face  for  head  of   rib;    r'.  face  for  tubercle  of  rib;    s.  neural 

zygapophysis ;  z'.  posterior  zygapophysis. 

Both  figures  are  one-fourth  natural  size. 


spine;    z.  anterior 


FtGDRB  91. — First  dorsal  vertebra  of  Tinoceras  anceps,  Marsh  (No.  1030);  front  view. 
FiCUEE  98 — The  same  vertebra;  side  view. 

nc.  neural  canal ;  z.  anterior  zygapophysis;  z'.  posterior  zygapophysis ;    s.  neural  spine. 
Both  figures  are  one-fourth  natural  size. 


THE   DORSAL   VERTEBKiE.  81 

The  first  dorsal  in  the  type  specimen  of  Tinoceras  anceps  (number 
1030)  is  shown  in  figures  97  and  98,  on  page  80.  In  other  specimens 
of  Tinoceras,  this  vertebra  presents  the  same  general  characters. 

The  principal  dimensions  of  a  first  dorsal  vertebra  of  Dinoceras,  and 
of  this  vertebra  in  the  type  specimen  of  Tinoceras,  are  given  below. 

MeasuremetiCs  of  First  Dorsal  Vertebra.     {Dinoceras  luirahile,  No.  1255.) 

m. 

Length  of  centrum,  along  floor  of  neural  canal,   .048 

Length  of  centrum,  along  inferior  surface, .058 

Vertical  diameter  of  anterior  face  of  centrum, . ... ■ .072 

Transverse  diameter  of  anterior  face  of  centrum,    .075 

Vertical  diameter  of  posterior  face  of  centrum, .073 

Transverse  diameter  of  posterior  face  of  centrum, .073 

Vertical  diameter  of  neural  canal, .__    .046 

Transverse  diameter  of  neural  canal, .005 

Greatest  diameter,  across  transverse  processes, . .210 

Diameter  of  jwe-zygapophyses, .030 

Distance  across  pre-zygapo[ihyses, --      .140 

Diameter  of  post-zygapophyses,  __ . .03 1 

Distance  across  post-zygapophyses, .    -. .115 

Diameters  of  anterior  face  for  head  of  rib, .030-.03S 

Diameters  of  posterior  face  for  head  of  rib, .027-037 

Diameters  of  face  for  tubercle  of  rib, .025  -.032 

Transverse  diameter  of  pedicel, .-     .044 

Antero-posterior  diameter  of  jjedicel, . __ _ 022 

Distance  between  faces  for  head  of  rib,   .015 

Measurements  of  First  Dorsal  Vertebra.     (Tinoceras  anceps, 'No.  1030.) 

m. 

Length  of  floor  of  neural  canal, .. .056 

Length  of  centrum,  along  under  surface,  : : .056 

Transverse  diameter  of  anterior  face  of  centrum, .    __.    .070 

Vertical  diameter  of  anterior  face  of  centrum  (approximate),  ..      ..    .063 

Transverse  diameter  of  posterior  face  of  centrum, .080 

Vertical  diameter  of  posterior  face  of  centrum, .066 

Transverse  diameter  of  neural  canal, __. .068 

Vertical  diameter  of  neural  canal  (approximate), .037 

Diameteis  of  anterior  capitular  face, .03 1-035 

Diameters  of  posterior  capitular  face, .033-040 

Antero-posterior  diameter  of  pedicel, .030 

Transverse  diameter  of  pedicel, .029 

Diameter  of  vertebra,  across  transverse  jjrocesses, .175 

11 


82 


DINOCERATA. 


The  Second  Dorsal  Vertebra. 
(Plate  XXIII;  and  woodcuts  99-100,  below.) 

The  second  dorsal  vertebra  in  Dinoceras  mirahile  (number  1255)  is 
especially  distinguished  from  the  one  last  described  by  the  neural  spine, 
which  is  massive,  and  more  inclined  backward.  The  neural  canal  is 
sub-triangular  in  outline.  Tlie  pre-zygapophyses  are  much  smaller,  less 
elevated,  and  look  more  directly  upward.  The  centrum  is  somewhat 
longer  than  that  of  the  first  dorsal,  and  more  expanded  transvei'sely. 
This  vertebra  is  represented  in  Plate  XXIII. 

The  second  dorsal  vertebra  of  Dinoceras  mirahile  (number  1212)  has 
the  neural  spine  still  more  massive,  the  neural  canal  more  expanded 
transversely,  and  the  articular  faces  of  the  centrum  more  nearly  circular, 
as  shown  in  figures  99  and  100,  below. 

In  the  genus  Tinoceras,  the  second  dorsal  presents  the  same  general 
features  as  in  the  vertebra  above  described. 


Figure  99. — Secimd  Uui^al  Vfiteljiu  uf  iJmoceras  mirable,  Marsh  (Xo.  1212):  frout  view. 
Figure  100. — The  same  vertebra ;  side  view. 

n.  neural  canal ;  s.  neural  spine ;  z'.  posterior  zygapophysis. 

Both  tioures  are  one-fourih  natural  size. 


The  more  important  measurements  of  the  second  dorsal  vertebra  of 
one  specimen  of  Dinoceras  are  as  follows : 


THE   DORSAL    VERTEBRA. 


83 


Measurements  of  Second  Dorsal  Vertebra.     {Dinoceras  mirabile.  No.  1255.) 

Length  of  centrum,  along  floor  of  neural  canal,    . 048 

Length  of  centrum,  along  under  surface, .060 

Transverse  diameter  of  anterior  face  of  centrum,    .073 

Vertical  diameter  of  anterior  face  of  centrum, .075 

Transverse  diameter  of  posterior  face  of  centrum, . .075 

Vertical  diameter  of  posterior  face  of  centrum, - -.  — .070 

Transverse  diameter  of  neural  canal,    .. . .---  .-- .065 

Vertical  diameter  of  neural  canal, _    —     .057 

Diameters  of  anterior  capitular  face,  _ ,_ —  .  — .0'29-.033 

Diameters  of  posterior  capitular  face, -. --  .. .0.!9-.040 

Antero-posterior  diameter  of  pedicel,   .025 

Transverse  diameter  of  pedicel,    -040 

Diameter  of  vertebra,  across  transverse  processes,  —  _ —      .200 

Diameter  of  vertebra,  across  post-zygapophyses, — —      .080 

Least  transverse  diameter  of  neural  spine, .035 

The  Third  Dorsal  Vertebra.  (Woodcuts  101  and  102,  below.) 
The  third  dorsal  vertebra  in  the  genera  Dinoceras  and  Tinoceras  differs 
from  the  vertebra  in  front  of  it,  in  having  the  neural  spine  less  robust,  and 
the  transverse  processes,  and  the  faces  for  the  heads  of  the  ribs  on  the 
centrum,  more  elevated.  The  centrum  itself  is  less  expanded  transversely, 
and  its  leng'th  is  greater. 

Fig.  101.  Fig-  1C2. 

J 

FiGtJEE   101. — Third  dorsal  vertebra  of  Uintatherium  segne,  Marsh  (No.  1194);   front  view. 
Figure  102. — The  same  vertebra  ;  side  view. 

d.  transverse  process;  nc.  neural  caual ;  r.  face  for  head  of  rib;  r'.  face  for  tubercle  of  rib;  s.  neural 

spine. 

Both  figures  are  one-fourth  natural  size. 

The  third  dorsal  in  Uintatherium  segne  (number  1194)  shows 
essentially  the  same  characteristics,  and  is  represented  in  figures  101  and 
102,  above. 


84 


DINOCERATA. 


The    Median    and    Posterior    Dorsal    Vertebra. 
(Plate  XXIV;  and  woodcuts  103-105,  below.) 

In  the  dorsal  vertebra  of  Dinoceras,  behind  the  third,  the  neural 
spine  gradually  becomes  shorter  and  weaker,  and  the  neural  canal, 
transversely  oval  in  outline.  The  transverse  processes  are  more  elevated, 
and  sliorter.  The  centrum  becomes  more  compressed  below,  so  that 
the  articular  faces  are  sub-triangular  in  outline,  as  shown  in  Plate 
XXIV,  figure  2. 

In  the  posterior  dorsals,  the  neural  spine  is  quite  short,  and  weak. 
The  anterior  zygapophyses  have  their  articular  faces  recurved,  as  in  the 
ruminant  mammals.  The  neural  canal  is  a  broad  oval  in  transverse 
outline.  The  transverse  processes  are  much  elevated,  and  the  articular 
faces  for  the  ribs  on  these,  and  on  the  centrum  below,  gradually  become 
smaller.  The  centrum  is  longer,  distinctly  keeled  below,  and  its  articular 
faces  are  triangular  in  outline,  the  three  sides  being  nearly  equal.  These 
features  are  shown  in  figures  103-105. 

The  last  dorsal  vertebra  of  Dinoceras  mirabile  (number  1215)  is 
represented  in  Plate  XXIV,  figures  5-9.  A  posterior  dorsal  of  another 
species  is  shown  below. 


Figure  103. — Posterior  dorsal  vertebra  of  Dinoceras  lucare,  Marsh  (No.  1038);  front  view. 
Figure  104. — The  same  vertebra;  side  view. 
Figure  105. — The  same  vertebra  ;  back  view. 

n.  neural  canal ;  r.  face  for  head  of  rib  ;  r'.  face  for  tubercle  of  rib  ;  «.  neural  spine ;  z.  anterior 

zygapophyses  ;  z'.  posterior  zygapophysis. 

All  the  figures  are  one-fourth  natural  size. 


THE   LUMBAR   VERTEBRA.  85 

The  Lumbar  Vertebra. 
(Plates  XXV  and  XXVI.) 

The  last  four  lumbar  vertebrae  of  the  type  specimen  of  Dinoceras 
mirabUe  (number  1036)  are  preserved,  and  are  figured  in  Plates  XXV  and 
XXVI.  The  centra  are  proportionally  much  longer  than  in  the  mastodon, 
and  the  most  anterior  of  the  four  is  excavated  at  the  sides,  and  keeled 
below,  so  as  to  be  nearly  triangular  in  a  vertical  section  near  the  middle. 
The  excavation  becomes  less  decided  in  the  succeeding  vertebra^,  which 
are  more  nearly  circular  in  section.  The  keel  disappears  upon  the  last 
lumbar,  wdiich  has  its  under  surface  strongly  roughened,  especially  near 
the  posterior  margin. 

The  epiphyses  of  all  these  vertebrae  are  imperfectly  united  with  the 
centra,  and  are  deficient  in  ossification  near  the  center,  forming  only  thin, 
and,  in  some  cases,  narrow  rings  of  bone.  The  deficiency  of  ossification 
increases  the  apparent  concavity  of  the  articular  faces  of  the  centrum. 
These  faces  also  become  more  oval  transversely  on  the  posterior  vertebrae, 
and  especially  upon  the  last  lumbar  vertebra. 

The  neural  canal  in  all  the  lumbar  vertebrae  is  large,  but  has  been 
considerably  reduced,  in  the  vertebras  of  this  specimen,  by  crushing-. 

The  zygapophyses  in  the  lumbar  region  are  strongl}-  articulated 
together.  The  pre-zygapophyses  present  a  curved  surface,  bending 
around,  and  firmly  grasping,  the  semi-cylindrical  post-zygapophyses, 
which  are  inserted  into  them.  This  form  of  articulation  is  found  among 
living  Artiodactyls,  and  existed  also  in  the  Oreodons  of  the  Miocene ; 
while  in  the  Perissodactyl  group,  and  in  Proboscidians,  the  zygapophyses 
of  this  region  are  loosely  applied  to  each  other  by  nearly  flat  surfaces. 

The  keel  on  the  under  surface  of  the  centrum  is  stout  and  short  on  the 
second  vertebra  from  the  sacrum,  where  it  first  appears  in  this  specimen, 
and  is  strongest  on  the  anterior  part  of  the  centrum.  On  the  next 
preceding  vertebra,  it  is  somewhat  thinner,  but  more  elongated,  extending 
along  the  whole  under  surface  of  the  centrum.  On  the  fourth  vertebra 
from  the  sacrum,  it  becomes  thin,  and  even  sharp  in  front. 


86  DINOCERATA. 

The  transverse  processes  are  flattened,  especially  above,  and  directed 
nearly  horizontally  outward.  They  are  much  more  elongated  than  in  the 
mastodon,  and  appear  to  have  been  proportionally  much  stronger  than  in 
the  tapir. 

The  principal  dimensions  of  four  lumbar  vertebrae  of  the  type 
specimen  of  Dinoceras  mirabile  are  as  follows  : 

Measurements  of  Fourth  Lumhur  Vertebra  from  Sacrum.     [Dinoceras  mmihile.  No.  1036.) 

m. 
Length  of  centrum  (anterior  epiphysis  wanting), .080 

Vertical  diameter  of  centrum, .087 

Vertical  diameter  of  posterior  face  of  centrum, ._^ .075 

Transverse  diameter  of  posterior  face  of  centrum  (approximate), .088 

Measurements  of  Third  Lumbar  Vertebra  from,  Sacrum.     (Dinoceras  mirabile,  No.  10.36.) 

m. 

Length  of  centrum, -, .08.5 

Transverse  diameter  of  anterior  epiphysis, .091 

Vertical  diameter  of  anterior  epiphysis, .080 

Transverse  diameter  of  posterior  epiphysis, .-.       .091 

Vertical  diameter  of  posterior  epiphysis, ._-      .078 

Measurements  of  Second  Lumbar  Vertebra  from  Sacrmn.     [Dinoceras  niirabile,'So.  1036.) 

m. 

Length  of  centrum,   .. -       .086 

Transverse  diameter  of  anterior  epiphysis  (approximate), .090 

Vertical  diameter  of  anterior  epiphysis, .-    080 

Transverse  diameter  of  posterior  epiphysis  (approximate), .095 

Vertical  diameter  of  posterior  epiphysis, .083 

Measurements  of  last  Lumbar  Vertebra.     [Dinoceras  mirabile,  No.  1036.) 

m. 

Length  of  centrum,  _ .-- .083 

Transverse  diameter  of  anterior  epiphysis  (approximate),  .095 

Vertical  diameter  of  anterior  epiphysis, .    080 

Transverse  diameter  of  posterior  epiphysis  (approximate), 105 

Vei'tical  diameter  of  posterior  epiphysis, 075 


CHAPTER    YII. 

THE    FORE    LIMBS. 
(Plates  XXVII-XXXVIII,  LV,  and  LVI.) 

The  limb  bones  in  the  Dinocerata  are  nearly  or  quite  solid,  and  this 
is  true  of  all  the  skeleton,  a  portion  of  the  skull  alone  excepted. 

The  fore  limbs  in  the  Dinocerata  have  a  general  resemblance  to  those 
of  Proboscidians.  The  different  segments,  however,  are  more  inclined  to 
each  other,  and  the  bones  that  compose  them  are  stouter,  and  more 
massive. 

The    Scapula.     (Plate  XXVII.) 

The  scapula  of  Dinoceras  mirabile,  in  its  general  form,  is  similar  to 
that  of  the  elephant.  It  is  triangular  in  outline,  with  the  anterior,  or 
coracoid,  border  slightly  longer  than  either  of  the  other  two  margins, 
which  are  about  equal  to  each  other,  if  the  glenoid  border  be  considered  as 
including  the  glenoid  cavity.  The  coracoid  border  is  excavated  by  a 
broad  rounded  emargination,  just  above  the  coracoid  process,  but  beyond 
this  sinus,  it  runs  nearly  straight  to  the  apex  of  the  bone,  which  is  more 
acute  than  in  the  mastodon. 

The  supra-scapular  border  is  moderately  curved  throughout,  and  the 
posterior  angle  appears  to  be  less  acute  than  in  the  Proboscidians.  The 
glenoid  border  is  nearly  in  a  line  with  the  glenoid  cavity,  so  that  the 
constriction  above  the  cavity  is  scarcely  evident  in  the  posterior  margin  of 
the  bone. 

87 


88  DINOCERATA. 

The  external  surface  of  tlie  scapula  is  divided  into  two  unequal  fossae. 
The  anterior  of  these,  or  pre-scapular  fossa,  extends  the  entire  length  of  the 
bone,  but  is  less  than  half  as  wide  as  the  post-scapular  fossa,  from  which  it 
is  divided  by  a  thick  and  stout  spine.  The  latter  is  less  elevated  than  in 
the  elephant  and  mastodon,  and  less  expanded,  but  extends  farther 
downward,  nearly  to  the  level  of  the  glenoid  cavity.  It  is  destitute  of  the 
curved  posterior  process  seen  in  tlie  elepliant  and  mastodon. 

The  post-scapular  fossa  is  strongly  roughened  near  the  posterior  angle, 
which  is  rounded. 

The  glenoid  cavity  is  onh"  moderately  concave  transversely,  and 
somewhat  broader  behind  than  before. 

The  inner  surface  of  the  scapula  is  for  the  most  part  smooth,  except 
over  a  large  quadrilateral  area  in  the  region  of  tlie  apex.  The  supra- 
scapular border  is  ossified  separately  from  the  bodv  of  the  bone. 

The  coracoid  is  firmly  united  to  the  scapula  in  Dlnoceras  mirabile 
(number  1215),  and  forms  a  rounded  salient  process,  projecting  freely  in 
front  of  the  glenoid  cavity.  Seen  from  the  front,  it  appears  to  be  tri-lobed 
in  outline. 

The  main  dimensions  of  the  scapula  in  one  specimen  of  Dlnoceras 
mlrahile  are  as  follows : 

Measurements  of  Left  Scapula.     {Dinoceras  mirabile,  No.  1215.) 

Aiitero-postei'ior  diameter  of  glenoid  cavity, .115 

Transverse  diameter  of  glenoid  cavity,   __- -.-. .090 

Greatest  vertical  diameter  of  scapula, ' .575 

Greatest  horizontal  diameter, .... ...  .480 

Lengtli  of  coracoid  border, _  .570 

Length  of  supra-scapular  border, . ..  .390 

Length  of  glenoid  border, .350 

Height  of-  acromion  above  glenoid  cavity, .120 

Trreatest  diameter  of  pre-seapuL^T  fossa, . .    .140 

Greatest  diameter  of  post-scapular  fossa, .310 


THE   FORE   LIMBS.  89 

The    Humerus. 
(Plate  XXVIII;    and  woodcuts  106-107,  below.) 

The  liLinierus  of  D'moceras  is  a  strong  bone,  presenting-  roughened  and 
tuberculated  surfaces,  evidently  for  the  attachment  of  powerful  muscles. 
In  this  respect,  it  is  in  strong  contrast  with  the  comparatively  smootli 
femur,  and  a  glance  at  the  structure  of  the  skeleton,  as  shown  in  the 
restorations  in  Plates  LV  and  LVI,  will  suggest  a  reason  for  this 
difference. 

The  hind  leg  of  Dinoceras,  like  that  of  the  elephant,  could  be 
straightened,  so  that  the  weight  of  the  hinder  part  of  the  body  was 
supported  by  a  vertical  column  of  bones,  rising-  from  the  ankle  joint  to  the 
pelvis,  and  comparatively  little  muscular  action  was  required  to  keep  the 
bones  in  the  requisite  position.  The  elbow  joint,  on  the  contrary,  was  not 
capable  of  sufficient  extension  to  bring'  the  radiiis  and  ulna  into  a  line 
with  the  humerus,  but  the  Aveight  of  the  fore  part  of  the  body  was 
supported,  as  in  ordinary  quadrupeds,  by  a  long  column  with  more  or  less 
flexure  near  the  middle.  Constant  muscular  action  was  therefore  necessary 
to  sustain  the  weight  of  this  part  of  the  body.  The  lieavv  and  strongly 
armed  bead  added  still  more  to  the  muscular  efforts  required  of  the  fore 
limbs,  during  progression,  or  even  while  standing-  at  rest. 

The  proximal  end  of  the  humerus  (Plate  XXVIII,  figure  3,ffl)  presents 
a  large  rounded  articular  face,  or  head,  more  convex  antei'O-posteriorly 
than  from  side  to  side.  The  axis  of  the  head  of  the  humerus  forms  an 
angle  of  nearly  30°  with  that  of  the  shaft.  This  angle,  while  greater  than 
that  seen  in  the  same  bone  of  the  elephant,  is  much  less  than  in  most 
quadrupeds. 

The  great  tuberosity  of  the  humerus  is  prominent,  but  not  elevated, 
and  is  separated,  by  a  shallow  and  narrow  bicipital  g-roove,  from  the  low 
lesser  tuberosity.  The  great  tuberosity  is  about  as  large  as  in  the 
elephant,  but  does  not  extend  so  high,  not  rising  to  tbe  head  of  the 
humerus.  It  is  stiongly  tuberculated  and  roughened,  and  is  continued 
down  the  anterior  and  outer  part  of  the  shaft  into  a  prominent  ridge  below 

12 


90  DINOCERATA. 

the  middle  of  the  bone.  Here  it  unites  with  the  oblique,  and  well 
developed,  deltoid  ridge,  then  descends  rapidly,  and  ends  in  a  roughened 
surface  just  above,  and.  inside  of,  the  coronoid.  fossa.  The  deltoid  ridge  is 
strong,  oblique,  and  elongated,  as  is  well  shown  in  the  back  view  of  the 
humerus,  Plate  XXVIII,  figure  3.  It  does  not,  however,  rise  into  a 
hook-like  process,  as  in  the  rhinoceros.  The  bicipital  groove  is  single, 
as  in  the  elephant,  and  presents  no  median  ridge.  The  lesser  tuberosit}' 
is  small  and  low,  and  wholly  below  the  head,  which  is  broad  and 
extensive,  covering  much  the  greater  part  of  the  superior  aspect  of  the 
bone,  and  extending  forward  to  the  bottom  of  the  bicipital  groove. 

The  shaft  of  the  humerus  is  most  constricted  at  a  point  nearly  three- 
fourths  of  the  way  toward  the  distal  end,  and  here  is  distinctly  triangular 
in  section,  one  of  the  angles  projecting  forward,  as  seen  in  Plate  XXVIII, 
figure  1.  Above  and  below  this  point,  the  shaft  expands,  and  is  more 
flattened,  especially  distally.  Here  it  is  excavated  in  front,  as  usual,  by  a 
large  rounded  and  deep  coronoid  fossa,  placed  well  to\yard  the  outer,  or 
radial,  side,  as  shown  in  Plate  XXVIII,  figure  1.  The  posterior  surface 
is  hollowed  out,  medially,  by  a  comparatively  shallow  anconeal  fossa,  as 
shown  in  figure  3  of  the  same  Plate.  The  coronoid  fossa  in  some 
specimens  (number  1224)  is  even  deeper  than  the  anconeal,  and  is  always 
distinct  and  rounded.  The  anconeal  fossa  is  also  rounded  in  general 
outline,  median  in  position,  and  is  carried  but  little  below  the  trochlear 
articular  face. 

The  posterior  surface  of  the  humerus  is  bounded,  on  the  inner  side, 
by  a  ridge  running  almost  the  entire  length  of  the  shaft.  This  ridge 
commences  above,  near  the  posterior  part  of  the  lesser  tuberosity,  and  the 
postero-internal  angle  of  the  head,  and  runs  nearly  straight  down  the  shaft 
of  the  humerus,  terminating  in  an  expanded  and  tubercular  tract,  on  the 
inner  condyle.  On  this  ridge,  and  about  the  middle  of  the  shaft,  nearl}' 
opposite  the  strongest  part  of  the  deltoid  ridge,  is  another  roughened  area, 
often,  as  in  the  specimen  figured  (Plate  XXVIII,  figures  1,  2  and  3), 
rising  into  a  distinct  trochanter-like  eminence,  appfi.rently  for  the  insertion 
of  the  latissimus  dorsi  muscle.     At  the  lower  end  of  the  humerus,  tliis  ridge 


THE   FORE   LIMBS.  91 

ends  in  a  large  and  prominent  inner  cond3?le,  which  does  not,  hoAvever, 
extend  far  back  of  the  trochlear  surface,  as  seen  in  Plate  XXVIII,  figure  l,a. 

The  outer  condyle  is  nearly  on  the  same  level  as  the  inner,  and 
extends  to  about  the  same  distance  laterally,  from  the  axis  of  the  bone,  as 
seen  in  Plate  XXVIII,  figures  1  and  3.  Above,  it  descends  rapidly  to  the 
shaft  of  the  bone,  and  presents  only  a  short  and  moderately  rugose,  or 
nearly  smooth,  supinator  ridge. 

The  trochlear  articulation  considerably  resembles  that  of  the 
elephant,  but  is  placed  a  little  more  obliquely  to  the  axis  of  the  bone. 
The  radius  articulated,  during  life,  with  the  whole  of  the  anterior  part  of 
this  surface,  and  tlie  ulna,  with  the  whole  of  the  posterior  part,  the  former 
bone  being,  at  the  proximal  end,  in  front  of  the  latter,  and  scarcely  at  all 
on  the  outer  side.  The  outer  part  of  the  trochlear  surface  is  more  rounded 
in  both  directions  than  the  inner,  the  surface  of  which  is  only  moderately 
curved  in  a  transverse  direction. 

The  shaft  of  the  humerus  is  more  or  less  cancellated  within,  as  shown 
in  the  woodcuts,  figures  106  and  107,  but  is  destitute  of  any  medullary 
cavity. 

Fig.  106.  Fig.  107. 


^^S 


FiGUEE  106. — Section  of  humerus  of  Dinoceras  mirabile,  Marsh  (No.  1215) ;  near  proximal  end. 
Figure  107. — Section  of  humerus  of  Dinoceras  mirabile  (So.  1208);  below  middle. 
Botli  figures  are  one-fourtli  natural  size. 

Measurements  of  the  humerus  in  four  individuals  of  Dinoceras  are  as 

follows : 

Measurements  of  Left  Humerus.     [Dinoceras  mirabile^  No.  1245.) 

m. 

Total  length  of  humerus, .... ._.    --  —  -  .655 

Antero-posterior  diameter  of  head, . .136 

Transverse  diameter  of  head, .120 

Greatest  diameter  of  proximal  end, -220 

Least  antero-posterior  diameter  of  shaft,  -    -070 

Least  transverse  diameter  of  shaft, ■--- -080 


92  DINOCERATA. 

m. 

Transverse  diameter,  through  condyles, .200 

Transverse  diameter  of  trochlear  surface, '_ .127 

Antero-posterior  diameter  of  trochlear  surface,  ulnar  side, .109 

Antero-posterior  diameter  of  trochlear  surface,  radial  side, .091 

Antero-posterior  diameter  of  trochlear  surface,  least, .078 

Thickness  of  bone  between  coronoid  and  aneoneal  fossa>, .. .016 

Measurements  of  Left  Humerus.     [Dinoceras  mirabile.  No.  1208.) 

m. 

Least  antero-posterior  diameter  of  shaft, .    —  . __  .064 

Transverse  diameter,  through  condyles, .. .  .184 

Transverse  diameter  of  trochlear  surface, _. .124 

Antero-posterior  diameter  of  trochlear  surface,  ulnar  side, .    _.  .100 

Antero-posterior  diameter  of  trochlear  surface,  radial  side, .095 

Antero-posterior  diameter  of  trochlear  surface,  least, __. .080 

Thickness  of  bone  between  coronoid  and  aneoneal  fossie, .Ola 

Jfeasureiuents  of  JRight  Iliimenis.     [Diiioceras  mirabile.  No.  1212.) 

m. 

Least  antero-posterior  diameter  of  shaft, . .058 

Transverse  diameter  through  condyles, . .183 

Transverse  diameter  of  trochlear  surface, - .115 

Antero-posterior  diameter  of  trochlear  surface,  ulnar  side, .098 

Antero-posterior  diameter  of  trochlear  surface,  radial  side, ...  .080 

Antero-posterior  diameter  of  trochlear  surface,  least, .072 

Thickness  of  bone  between  coronoid  and  aneoneal  fossa^, .014 

Measurements  of  JxigJ:t  Uumeiiis.     [Dinoceras  mirabile,  No.  1215.) 

m. 

Antero-posterior  diameter  of  head, .. .140 

Transverse  diameter  of  head, .138 

Greatest  diameter  of  jwoximal  end, .220 

Antero-posterior  diameter  of  trochlear  surface,  ulnar  side, .116 


The  Forearm.  (Plates  LV  and  LVI.) 
The  two  bones  of  the  forearm  in  tlie  B'mocerata  are  quite  distinct 
throughout  in  all  the  specimens  observed,  and,  exclusive  of  the  olecranon 
process  of  the  idna,  differ  but  little  in  size.  The  articular  surface  for  the 
humerus  is  formed  in  about  equal  parts  by  each  bone,  except  that  it  is 
medially  produced  back\Yard  on  the  ulna  upon  the  beak  of  the  olecranon. 
The  distal  articular  face  for  the  carpus  was  borne  more  by  the  radius 
than  the  ulna,  but  the  inequality,  in  size,  of  the  articular  faces  was 
comparatively  slight.      The  lunar  articulated  distinctly  with  both  bones. 


THE  FORE   LIMBS.  93 

Tlie  articular  surfaces  of  the  radius  and  the  uhia  for  each  other  were 
nearly  parallel  with  the  axes  of  those  bones,  and  allowed  of  little  else  than 
a  slig'ht  antero-posterior  gliding  motion.  Tlie  roughened  and  co-adapted 
surfaces  of  the  bones  indicate  that,  during  life,  all  movements  of  pronation 
and  supination  were  prevented  by  po^verful  ligaments. 

The  radius  does  not  appear  so  distinctly  to  cross  the  ulna  as  in  the 
Proboscidians,  being,  at  the  upper  end,  in  front  of  that  bone,  and 
proportionally  much  larger,  then  passing  down  obliquely  inward  to  a 
position  within  the  distal  end  of  the  ulna. 

The  proportion  of  the  two  bones  to  each  other  is  much  nearer  that 
seeu'in  "the  rhinoceros  and  hippopotamus,  than  that  in  the  elephant.  • 


The  Eadius.     (Plate  XXIX;  and  woodcuts  108-109,  below.) 

The  radius  in  Dinoceras  is  a  strong  bone,  with  its  shaft  about  equal  in 
size  to  that  of  the  ulna.  It  is  considerably  larger  than  that  bone  at  the 
lower  end,  and  smaller  at  the  upper  end. 

The  head,  or  superior  articular  face,  occupies  the  entire  surface  of  the 
proximal  end.  This  surface  is  elongate  oval  in  outline,  the  long  diameter 
being  placed  transversely,  and  nearly  twice  as  great  as  the  short  diameter. 
The  latter  is  antei'o-posterior  in  direction,  in  the  ordinary-,  nearly  vertical 
position  of  the  bone.  It  crosses  the  surface  of  the  bone  nearly  in  the 
middle,  instead  of  toward  the  inner  side  of  the  middle,  as  in  most 
Ungulates.  Antero-posteriorly,  the  articular  surface  is  concave 
throughout,  but  transversely,  it  is  convex  on  the  inner  side,  and  concave 
on  the  outer  side  of  the  middle  line.  The  inner  half  of  the  articular 
surface  is  thus  traversed  by  a  low  antero-posterior  ridge,  or  elevation, 
which  moves  upon  tlie  groove  in  the  distal  articular  face  of  tlie  humerus. 

The  proximal  surface  of  tlie  radius  differs  from  that  of  the  elephant  in 
being  proportionally  much  larger,  and  extending  quite  aci-oss  the  Immeral 
articular  surface.  It  differs  from  that  of  the  tapir,  and  the  liippopotamus, 
in  having  only  a  single  antero-posterior  ridge,  as  in  the  rhinoceros.  It 
still  differs  from  that  of  the  rhinoceros,  in  the  fact,  that  a  transverse  section 


94  DINOCERATA. 

is  concave  in  its  outer  half,  and  convex  in  its  inner  half,  while  in  the 
rhinoceros,  such  a  section  is  concave  at  each  end,  and  convex  only  near 
the  median  portion. 

On  the  side  of  the  radius  toward  the  ulna,  is  a  narrow  articular 
surface  for  that  bone,  becoming  broader  toward  the  outer  end. 

The  shaft  of  the  radius  is  smallest  at  a  point  about  one-third  of  the 
way  from  the  proximal,  toward  the  distal  end.  Above  this  point,  the 
bone  expands  rather  rapidly  toward  the  head.  It  is  much  roughened, 
especially  on  the  side  toward  the  ulna,  with  which,  however,  it  forms  no 
bony  union;  nor  are  the  bones  roughened,  or  grooved  for  close  adaptation 
to  each-  other,  as  in  the  tapir  and  rhinoceros.  The  bicipital  tuberosity  is 
well  developed,  and  placed  rather  low  down  on  the  side  of  the  shaft, 
instead  of  on  the  front  part  of  it.  The  distal  end  of  the  shaft  is  large, 
rough,  and  oblique,  and  presents  no  smooth  grooves  for  tendons. 

The  distal  articular  face  is  divided  by  a  median  ridge  into  two 
sub-equal  facets,  for  the  scaphoid  and  lunar  bones  of  the  carpus.  These 
facets  are  confluent  along  the  summit  of  the  median  ridge.  That  for  the 
scaphoid  is  semi-circular  in  outline,  and  concave  in  both  directions,  while 
that  for  the  lunar  is  four-sided,  much  broader  in  front  than  behind,  and 
concave  throughout.  Near  the  back  part  of  the  ulnar  side  of  this  facet, 
the  articular  face  is  continued  into  a  small  tract  on  the  lateral  surface  of 
the  radius,  where  it- comes  in  contact  with  the  ulna. 

The  shaft  of  the  radius  has  an  interior  cancellated  structure,  as  shown 
in  the  figures  below,  but  no  medullary  cavity 


Figure  108. — Section  of  radius  of  Diiioceras  mirabile,  Marsh  (No.  1195). 
Figure  109. — Section  ol  raiiua  oi  Dinoceras  mirabile,  Maish  (No.  1234). 

Both  figures  are  one-fourth  natural  size. 

Measurements  of  the  radius  in  three  individuals  of  Dinoceras  are  the 
following : 


THE   FORE   LIMBS.  95 

Measurements  of  Left  Radius.     [Dinoceras  mirabile,  No.  1208.) 

m. 

Total  length  of  radius, .380 

Greatest  diameter  of  proximal  end, .098 

Antero-posterior  diameter  of  proximal  end, .061 

Least  diameters  of  shaft, 032-.053 

Transverse  diameter  of  distal  end, _... .102 

Antero-posterior  diameter  of  distal  end, . 080 

Diameters  of  articulation  for  humerus,    .052-.094 

Antero-posterior  diameter  of  face  for  scajjhoid, .055 

Transverse  diameter  of  face  for  scaphoid, ..       .039 

Antero-posterior  diameter  of  face  for  lunar, .056 

Transverse  diameter  of  face  for  lunar, .045 

Transverse  diameter  of  distal  articular  surfaces, .082 

3feasHreme?i(s  of  Left  Madius.     {Dinocems  mirabile,  l.^o.    1206.) 

m. 

Total  length  of  radius, .254 

Greatest  diameter  of  proximal  end, ... .116 

Antero-posterior  diameter  of  proximal  end, .071 

Least  diameters  of  shaft, . 062-.041 

Transverse  diameter,  distal  end, .011 

Antero-posterior  diameter,  distal  end, .097 

Diameters  of  articulation  for  humerus, 060-  108 

Antero-posterior  diameter  of  articulation  for  scaphoid, .065 

Transverse  diameter  of  articulation  for  scajAoid, .040 

Antero-posterior  diameter  of  articulation  for  lunar, : . .065 

Transverse  diameter  of  articulation  for  lunar, .055 

Transverse  diameter  of  distal  articular  surfaces, .093 

Meastirements  of  Right  Radius.     {Dinoceras,  No.  1548.) 

m. 

Length  of  radius, -_--.. .-_    .    .400 

Greatest  diameter  of  proximal  end, .112 

Antero-posterior  diameter  of  proximal  end, . .070 

Least  diameters  of  shaft, 063-.035 

Transverse  diameter  of  distal  end, .108 

Antero-posterior  diameter  of  distal  end, .. . .090 

Diameters  of  articulation  for  humerus, 060-.104 

Transverse  diameter  of  articulation  for  scaphoid, .047 

Antero-posterior  diameter  of  articulation  for  lunar,   .055 

Transverse  diameter  of  articulation  for  lunar, .045 

Transverse  diameter  of  distal  articular  surfaces, .        .092 


96  DINOCEKATA. 

The  Ulna.     (Plate  XXX;  and  woodcuts  110-111,  below.) 

The  ulna  in  the  JDinocerata  is  a  solid  and  heavy  bone,  longer  than  the 
radius,  as  usual,  by  the  length  of  the  olecranon  process.  Except  near  the 
distal  end,  it  is  larger  and  stouter  than  that  bone,  to  which  it  was  united  in 
life  by  ligaments  only,  but  in  such  a  manner  as  to  allow  of  little  motion 
between  them.  The  shaft  of  the  ulna  always  made,  even  at  its  utmost 
extension,  a  distinct  angle  with  that  of  the  humerus. 

The  ulna  in  Dinoceras  is  proportionally  less  robust  than  in  the 
elephant.  Its  distal  encl  is  comparatively  smaller  than  in  that  animal,  and, 
at  the  proximal  end,  a  much  smaller  proportion  of  the  articular  surface  for 
the  humerus  is  furnished  by  the  ulna. 

The  olecranon  process  is  robust,  as  in  the  Proboscidians,  but  it  is 
carried  farther  above  the  articular  surface,  and  less  directh"  behind  it,  than 
in  that  group.  It  is  much  higher  within  than  without,  and  posteriorly,  it  is 
strongly  roughened  as  low  down  as  the  middle  of  the  humeral  articulation. 
It  is  only  moderately  produced  backward,  and  descends  into  a  broad 
ridge,  insensibly  blending  below  with  the  shaft  of  the  bone. 

Below  the  humeral  articular  surface,  the  shaft  of  the  ulna  is 
sub-triangular  in  section,  or,  near  the  distal  end,  some\^hat  quadrilateral. 
Along  the  posterior  and  outer  side  of  the  bone,  is  a  rounded  ridge,  running 
from  the  olecranon  process  above,  to  the  outer  angle  of  the  articular  face 
below. 

The  face  by  which  the  idna  is  applied  to  the  radius  is  broadl}- 
excavated,  and  strongly  roughened  above,  '\vhere  it  is  nearly  on  the  front 
surface  of  the  bone.  It  is  moderately  flattened  along  the  shaft  of  the 
bone,  and  is  carried  around  to  the  inner  surface  toward  the  distal  end, 
where  it  is  broad,  flat,  and  distinctly  roughened. 

The  anterior  face  of  the  bone  is  also  flattened  near  the  distal  end, 

and  separated  from  the  outer  face  by  a  ridge,  which  extends  upward  to 

■  near  the  middle  of  the  shaft.     Tlie  postero-external  face  of  the  bone  is 

flattened,  or  only  moderately  rounded,  and  is  somewhat  excavated  behind 

the  lower  part  of  the  humeral  articulation. 


THE   FORE   LIMBS.  97 

This  articulation  presents  a  striking  difference  in  direction  from  that 
seen  in  the  corresponding  face  on  the  nhia  of  the  elephant  and  mastodon. 
It  is  so  placed  on  the  shaft  of  the  bone  as  to  look  almost  directly  forward, 
and  only  veiy  slightly  upward,  instead  of  looking  nearly  upward,  as  in  the 
mastodon.  It  forms,  comparatively,  a  much  smaller  part  of  the  face  for 
the  humei'al  trochlea. 

In  shape,  this  articulation  is  distinctly  tri-lobate.  One  rounded  lobe, 
convex  from  side  to  side,  runs  backward  and  upward  to  the  summit 
of  the  beak  of  the  olecranon.  A  second,  and  large  lobe,  moderately 
concave  in  both  directions,  runs  inw^ard,  articulating  with  the  ulnar  portion 
of  the  trochlea  of  the  humerus.  An  outer,  small  and  flattened,  lobe 
articulates  with  the  posterior  part  of  the  radial  surface  of  the  trochlea. 
The  front,  or  lower,  outline  of  the  articular  face  is  modei-ately  concave, 
and  adapted  to  the  surface  of  the  radius  by  a  narrow  face,  becoming  wider 
toward  each  extremity. 

Tlie  distal  end  of  the  ulna  is  terminated  by  an  articular  surface,  which 
is  somewhat  quadrant-shaped.  The  inner  and  posterior  outlines  are 
nearly  straight,  and  meet  at  a  right  angle,  while  the  anterior  and  outer 
margins  are  formed  by  a  curved  line. 

This  face  is  convex  in  an  antero-posterior  direction,  strongly  so  behind. 
In  a  transverse  direction,  it  is  moderately  concave,  except  near  the  inner 
edge,  where  it  is  broadly  beveled  off,  for  union  with  the  lunar  bone  of 
the  carpus. 

Much  the  larger  part  of  the  distal  articular  face  of  the  ulna  articulated, 
during  life,  with  the  pyramidal  bone,  or  the  cuneiform  bone  of  mauA- 
anatomists. 

Posteriorly,  a  surface  was  presented  for  the  pisiform,  and,  on  the 
inner  side,  a  narrow  beveled  surface  united  with  the  lunar  bone. 

Farther  within,  and  on  the  surface  of  the  shaft  of  the  bone,  a  small 
surface  was  presented  to  the  radius,  although  the  two  bones,  as  ah-eady 
stated,  were  strongly  fixed,  during  life,  in  their  relation  to  each  other, 

13 


98  DINOCERATA. 


The  inner  texture  of  the  shaft  of  the  nlna  is  similar  to  that  of  the 
radius,  as  indicated  in  the  sections  represented  below,  figures  110  and  111. 

KiG.  nil.  Fig.  ill. 


FiG-URB  no. — Section  of  ulna  of  JDinoceras  lucare,  Marsh  (No.  lOSS). 
Figure  111. — Section  of  ulna  of  Binoceras  mirabile,  Marsh  (No.  1548). 

Eolh  figures  are  one-fourth  natural  size. 

The  principal  dimensions  of  the  ulna  in  three  individuals  of  JDinoceras 
are  as  follows : 

Measurements  of  Left  Ulna.     [Dinoceras  mirabile,  No.  1206.) 

m. 

Total  length  of  ulna, .530 

Diameters  of  proximal  end, .095-140 

Transverse  diameter  of  shaft,  behind  humeral  articular  face, .055 

Diameter  of  shaft,  through  humeral  articular  face, 097 

Diameters  of  shaft,  near  the  middle, ,_-    .(i57-.081 

Antero-posterior  diameter  of  shaft,  near  distal  end, . .085 

Transverse  diameter  of  shaft,  near  distal  end, .067 

Transverse  diameter  of  humeral  articulation,  greatest, .  143 

Transverse  diameter  of  humeral  articulation,  least, .060 

Antero-posterior  diameter  of  humeral  articulation,  at  the  middle, .      .085 

Antero-posterior  diameter  of  humeral  articulation,  inner  lobe,  - . .063 

Antero-posterior  diameter  of  humeral  articulation,  outer  lobe, .045 

Transverse  diameter  of  distal  articular  surface, .076 

Antero-posterior  diameter  of  distal  articular  surface, .070 

Least  and  greatest  diameters  of  diital  articular  surface, _    _.     .067-097 

Measurements  of  Right  Ulna.     {Dinoceras  mirabile,  ISo.  1232.) 

m. 

Total  length  of  ulna, .555 

Diameters  of  jjroximal  end, .098-130 

Transverse  diameter  of  shaft,  behind  humeral  articulation, .065 

Diameter  of  shaft,  through  hui-iieral  articulation, .103 

Diameters  of  shaft,  near  the  middle, .067-.077 

Antero-posterior  diameter  of  shaft,  near  di.-stal  end, .... • .095 

Transverse  diameter  of  shaft,  near  distal  end, .084 

Least  transverse  diameter  of  humeral  articulation,. — .058 

Antero-posterior  diameter  of  humeral  articulation,  at  the  middle,    . . .     .086 


THE    FOHE    LIMBS.  99 


Antero-posterior  diameter  of  humeral  articulation,  inner  lobe,. .066 

Transverse  diameter  of  distal  articular  surface,. -  .073 

Antei'o-posterior  diameter  of  distal  articular  surface, .061 

Greatest  diameter  of  distal  articular  surface, .090 

Measurements  of  Right  Ulna.     [Dinooeras  liicare,l^o.  1038.) 

m. 

Diameters  of  proximal  end  of  ulna  (approximate), . 070-103 

Diameter  of  shaft,  behind  humeral  articulation, .052 

Diameter  of  shaft,  through  humeral  articulation, . .088 

Greatest  transverse  diameter  of  humeral  articulation, .125 

Least  transverse  diameter  of  humeral  articulation, .052 

Antero-posterior  diameter  of  humeral  articulation,  at  the  middle, ... .090 

Antero-posterior  diameter  of  humeral  articulation,  inner  lobe, .  _ .062 

Antero-posterior  diameter  of  humeral  articulation,  outer  lobe, . . .038 


CHAPTER      YIII 


THE    FORE    LIMBS.        (Continued.) 

(Plates   XXXI-XXXVIII,    LIV,    LV   and   LVI). 

The  fore  foot  in  all  the  Binocerata  is  larger  than  the  hind  foot.  The 
bones  composing  it  are  comparatively  short  and  massive.  There  were 
five  well  developed  digits,  as  in  Proboscidians,  but  the  carpal  bones  were 
interlocked  with  the  metacarpals,  as  in  Perissodactyls.  The  general 
appearance  of  the  fore  foot  in  Binoceras  mirabile  is  well  shown  in  Plate 
LIV,  figure  1.  The  hind  foot  is  represented  in  figure  2  of  the  same  Plate. 
The  feet  were  plantigrade,  as  in  the  elephant,  and  in  their  more  important 
characters  were  much  like  those  of  Coryphodon. 

The  Carpal  Bones. 

(Plates  XXXI-XXXIV;   and  Avoodcuts  112-124,  below.) 

There  are  eight  separate  carpal  bones  in  the  fore  foot  of  all  the 
Binocerata,  and  a  ninth,  the  central  bone,  may  be  separate  in  very 
young  animals,  and,  in  adults,  either  lost  or  consolidated  with  the 
scaphoid,  or  the  trapezoid. 

101 


102  DINOCEUATA. 

The  Scaphoid. 

(Plate  XXXI,  figures  1-6,  Plate  LIV,  figure  1,  s; 

and  woodcuts  112-113,  below.) 

The  scaphoid  in  the  Dinocerata  is  a  peculiar  bone  of  characteristic 
shape.  It  is  quite  large,  its  length,  along  the  axis  of  the  limb,  being 
greater  than  that  of  any  other  bone  of  the  carpus.  Proximally,  it  presents 
a  strongly  rounded,  almost  hemispherical  surface,  for  articulation  with  the 
radius.  This  articular  face  covers  the  entire  proximal  end  of  the  bone, 
and  is  oblique  to  its  axis,  the  side  toward  the  lunar  being  much  higher 
than  the  opposite  side.  The  ulnar  side,  in  apposition  with  the  lunar, 
has  a  proximal  articular  surface  confluent  with  the  radial  surface,  and 
extending  less  than  one-fourth  the  length  of  the  bone. 

Distally,  the  scaphoid  presents  two  confluent  articular  faces,  one  for 
the  trapezium,  and  a  second  smaller  one,  somewhat  in  front  of  the  other, 
for  the  trapezoid.  These  two  faces  are  but  indistinctly  separated  from 
each  other,  and  are,  for  most  of  their  extent,  convex  in  both  directions. 

The  ulnar  side  of  the  bone  also  presents  two  confluent,  but  well 
marked,  articular  surfaces,  making  an  obtuse  angle  with  each  other.  Of 
these,  the  anterior  is  nearly  flat,  and  joins  the  lunar.  The  jiosterior  is 
more  convex,  and  adapted  to  the  magnum.  This  face  does  not  reach 
the  anterior  angle  of  the  bone,  so  that  the  magnum  is  supported  in  front 
by  the  lunar  alone,  but  articulates  behind  with  the  scaphoid  also. 

The  projection  supporting  these  two  faces  may  perhaps  represent  the 
central  bone,  coalesced  with  the  scaphoid.  The  latter  shows  no  face  for 
a  separate  central  bone. 

The  two  proximal  articular  faces  are  well  separated  from  the  four  at 
the  distal  end  of  the  scaphoid  bone  by  a  large  area  of  non-articular 
surface.  This  tract  becomes  elevated,  and  strongly  tuberculated,  on  the 
exterior  side  of  the  bone,  while  it  is  smoother,  and  somewhat  excavated, 
on  the  side  turned  toward  the  lunar  and  the  magnum. 

In  Plate  LIV,  figure  1,  the  scaphoid  and  lunar  bones  are  slightly  out 
of  position,  but  every  anatomist  will  see  their  true  relations  to  each  other. 

The  scaphoid  in  Dinoceras  laticeps  (number  1264),  like  most  others 
(except  number  1208),  shows,  near  the  distal  i)ortion  of  the  radial  side, 
below    the    rugose    surface,    a    deep    ami    somewliat    oblique    depression. 


THE    FORE   FEET. 


103 


The  scaphoid  in  two  specimens  of  Diuoceras  are  represented  in  the 
figures  below. 


Figure  112. — Left  scaphoid  of  Diuoceras  laticeps.  Marsh  (1261);  side  view 
FiGnRE  113. — Right  scaphoid  of  Dinoceras  mirabile,  Marsli  (1200) ;  side  view 
r.  face  for  radius;  im.  tace  for  trapezium;  tr.  face  for  trapr-zoid. 

Both  figures  are  one-half  natural  size. 

The    principal   dimensions  of  the   scaphoid   in    three    individuals    of 
Dinoceras  are  as  follows  : 

Measurements  of  Left  Scaphoid.     [Dinoceras  niirabih,  No.  1208.) 

m. 
Length  of  longitudinal  axis  of  scaphoid, .077 

Length  of  transverse  axes, ■,. . 049-049 

Antero-jjostei-ior  diameter  of  radial  articular  surface, .    _  _  _ 051 

Transverse  diameter  of  radial  articular  surface, .045 

Antero-posterior  diameter  of  distal  articular  surface, .070 

Transverse  diameter  of  distal  articular  surface, .044 

Measurements  of  Might  Scaphoid.     [Diuoceras  mirahile,  No.  1200.) 

Length  of  longitudinal  axis  of  scaphoid, .  _  ^ .    .(i7l 

Length  of  transverse  axes, ,_     .073-064 

Antero-posterior  diameter  of  radial  articular  surface, .__._., ...    .046 

Transverse  diameter  of  radial  articular  surface, 038 

Antero-posterior  diameter  of  distal  articular  surface, .066 

Transverse  diameter  of  distal  articular  surface, ...  .  _' .038 

Measurements  of  Left  Scaphoid.     [Dinoceras  laticeps.  No.  1264.) 

Length  of  longitudinal  axis  of  scaphoid, _ .086 

Length  of  transverse  axes, ... 051-.060 

Antero-posterior  diameter  of  radial  articular  surface, ... ...    .060 

Transverse  diameter  of  radial  articular  surface, .046 

Antero-posterior  diameter  of  distal  articular  surface, .082 

Transverse  diameter  of  distal  articular  surface, .050 


104  DINOCERATA. 

The  Lunae. 

(Plate  XXXI,  figures  7-12,  Plate  LIV,  figure  1,  I;    and 

woodcuts  114-116,  below.) 

The  lunar  bone  in  the  Binocerata  (Plate  XXXI,  figures  7-12)  bears 
some  resemblance  to  the  corresponding  bone  in  the  elephant,  but  ditfers 
widely  from  it  in  having  its  23roximal  siu-face,  for  articulation  with  the 
radius  and  iilna,  convex  throughout,  instead  of  being  for  tlie  most  part 
concave.  The  distal  surface,  also,  presents  two  distinct  articular  faces, 
instead  of  being  covered  with  a  single  large  face,  as  in  the  elephant. 

The  exterior  surface  of  the  lunar,  or  the  face  seen  in  front  when 
the  bone  is  in  its  natural  position  with  the  other  bones  of  the  foot, 
is  represented  on  Plate  XXXI,  figure  7.  This  surface  is  coarsely 
roughened,  and  is  widest  above.  Only  a  small  portion  of  the  edges  of 
any  of  the  articular  surfaces  can  be  seen  in  this  view. 

Tlie  inner  angle  of  the  distal  end  of  the  lunar  in  Dinoceras  (numbers 
1215,  1229,  and  1230)  is  truncated  by  a  small  face  for  articulation  with 
the  trapezoid  bone,  as  shown  in  figure  7,  and  also  in  woodcut  114,  below. 
On  one  specimen  (number  1575),  which  may  belong  to  Uintatherium,  this 
face  is  large  and  convex.  In  number  1254,  the  face  is  smaller  than  in 
the  specimens  figured.  The  articulation  of  the  lunar  with  the  trapezoid, 
or  perhaps  the  trapezo-central  bone,  occurs  also  in  Coryphodon,  Mastodon, 
and  the  elephant,  especially  the  African  spe'cies. 

The  lateral  surface  of  the  bone  turned  toward  the  scaphoid,  and 
articulating  with  it,  is  shown  on  Plate  XXXI,  figure  8.  This  side  has  two 
faces  for  articulation  with  the  scaphoid.  The  upper  one  of  these  runs 
along  nearly  the  whole  extent  of  the  superior  margin  of  the  bone,  and  is 
confluent  with  the  surface  for  articulation  with  the  radius,  and  hardly  to  be 
distinguished  from  it.  A  second  articular  face  for  union  with  the  scaphoid 
is  broader  and  more  flattened  than  tlie  first,  and  extends  along  rather 
more  than  half  of  the  distal  margin  near  its  front,  or  anterior,  end.  Behind 
this  articular  surface,  the  bone  is  produced  into  a  short,  hook-shaped 
process  sustaining  the  concave  portion  of  the  distal  articulations. 

The  posterior  surface  of  the  lunar  is  sliown  on  the  same  Plate,  figure 
9,  and  presents  no  articular  faces.      The  lateral  surface  turned  toward  the 


THE    I'^ORE   FEET. 


105 


pyramidal  is  shown  in  fig'ure  10.  Two  narrow  and  approximate  faces 
are  seen  on  this  surface,  becoming  somewhat  wdder,  and  approaching  each 
other  behind.  These  faces  vary  greatly  in  the  degree  to  which  they  are 
developed  in  different  specimens. 

The  upper,  or  proximal,  surface  is  confluent  with  the  ulnar  facet, 
while  the  lower,  or  distal,  one  is  continuous  with  the  face  for  the 
imciform,  but  usually  well  distinguished  from  it  by  a  ridge. 

The  proximal  surface  (figure  11),  articulating  with  the  radius,  is 
more  or  less  quadrangular  in  outline,  broader  in  front,  sometimes  so 
much  so  as  to  become  sub-triangular  in  outline  (number  1218).  It  is 
well  rounded  in  both  directions  throughout,  the  smooth  articular  face 
for  radius  and  ulna  being  cai-ried  over  on  each  side  to  join  both  the 
scaphoid  and  the  pyramidal  foces. 

Fu;.    115. 


Fig-.  114. 


FiGUKE  114. — Kight  lunar  of  Dinoceras  rairabile,  ilarsli  (No.  12:;0);  front  view. 
FiGDUB  115. — Left  lunar  of  Tiiioceras  ingens,  Marsh  (No.  1504);  bottom  vieTi'. 
FiGUEE  116. — Left  luuar  of  Tinoceras  ingens  (No.  1219) ;  front  view. 

m.  face  for  magnum;  p.  face  for  pyramidal ;  r.  face  for  radius;  •?.  face  for  scaphoid;  <r.  face  for  trapezoid; 

un.  face  for  unciform. 

All  the  figures  are  one-half  natural  size. 


The   distal    surface    (figure   12)   is   divided  into  two  articular  faces, 

supporting    in    part   the    mag-num    and    the    unciform.       These  faces   are 

confluent,  and  sometimes  hardly  to  be  distinguished  in  front,  but,  on  the 

posterior  part  of  the  surface,  they  are  separated  by  a  more  or  less  distinct 

rounded  ridge.     Both  these  faces  are  nearly  flat  transversely  in  front,  and 

somewhat    concave    behind.      In    an    antero-posterior  direction,  they  are 

convex  in  front,  and  conca.ve  behind, 
u 


106  DINOCERATA. 

In  the  right  hmar  oi  Dinoceras  mirabile  (number  1230),  the  distal  face 
for  articulation  with  the  scaphoid  makes  less  than  a  right  angle  with  the 
face  for  the  magnum,  instead  of  an  obtuse  angle,  as  in  most  other 
specimens. 

The  lunar  bone  in  Tinoceras  presents  no  articular  face  for  the 
trapezoid,  and  is  much  produced  posteriorly,  thus  distinguishing  it  from 
the  lunar  in  the  genus  Dinoceras.  Its  main  features  are  shown  in  the 
woodcuts,  115  and  116,  above. 

The  more  important  measurements  of  the  lunar  bone  in  four 
individuals  of  the  Dinocerata  are  as  follows  : 

Measurements  of  Right  Lunar.     {Dinoceras  mirabile,  No.  1230.) 

m. 

Length  of  longitudinal  axis  of  lunar, .050 

Antero-posterior  diameter  of  jjroximal  end,  — —       .059 

Transverse  diameter  of  proximal  end, .056 

Antero-posterior  diameter  of  distal  end, _ .075 

Transverse  diameter  of  distal  end, 046 

Measurements  of  Left  Lunar.     {Tinoceras  ingens.  No.  1503.) 

m. 

Length  of  longitudinal  axis  of  lunar, ..  .05 1 

Antero-posterior  diameter  of  proximal  end, .061 

Transverse  diameter  of  proximal  end, .053 

Antero-posterior  diameter  of  distal  end, __. .083 

Transverse  diameter  of  distal  end, .047 

In  tliis  specimen,  the  distal    face  for  the  scaphoid  is  quite  large,  and 
encroaches  on  the  face  for  the  magnum. 

Measurements  of  Eight  Lunar.     [Tinoceras  ingens.  No.  1504.) 

m. 

Length  of  longitudinal  axis  of  lunar, .054 

Antero-posterior  diameter  of  proximal  end, .062 

Transverse  diameter  of  jjroximal  end, .-  .065 

Antero-posterior  diameter  of  distal  end,   _. ._  .088 

Transverse  diameter  of  distal  end, .050 

Measurements  of  I^(ft  Lunar.     [Tinoceras  ingens.  No.  1246.) 

in. 

Length  of  longitudinal  axis  of  lunar, . .06 1 

Antero-posterior  diameter  of  proximal  end, .0615 

Transverse  diameter  of  proximal  end, -  .060 

Antero-postea'ior  diameter  of  distal  end, .092 

Transverse  diameter  of  distal  end,   ._ .053 


THE   FORE  FEET.  107 

The  Pyramidal. 

(Plate  XXXII,  figures  1-6,  Plate  LIV,  figure  l,p; 
and  Avoodcuts  117-118,  below.) 

The  pyramidal  bone  in  the  Dinocerata  bears  a  considerable 
resemblance  to  the  corresponding  bone  in  the  elephant,  and  has,  in 
general,  a  similar  shape,  and  similar  arrangement  of  articular  faces. 

Plate  XXXII,  figure  1,  represents  the  outer,  or  dermal,  surface  of  the 
bone,  as  seen  in  its  natural  position  in  the  foot,  and  shows  a  portion  only 
of  the  saddle-shaped  articular  face  for  the  ulna. 

The  anterior  view  of  the  bone  (figure  2)  shows  but  little  of  the 
articular  faces,  although,  on  the  side  turned  toward  the  lunar,  may  be 
seen  a  sliort  articular  face  running  along  the  distal  portion  of  the  surface. 
This  face  is  seen  more  clearly  in  figure  3,  and  is  confluent  with  the  lower, 
or  distal,  face  supporting  the  unciform,  but  makes  a  considerable  angle 
with  it. 

In  the  posterior  view  of  the  bone  (figure  4),  the  oblique  articulation 
for  the  pisiform  is  shown.  This  articular  face,  like  most  of  the  lateral 
ones  among  the  carpal  bones,  is  of  variable  shape,  and  often  fails  to  show 
tlie  deep  emargination  at  the  side,  seen  in  the  specimen  figured.  Ahtng 
the  upper  margin,  where  this  face  is  confluent  with  the  ulnar  articular 
face,  the  two  are  separated  by  a  nearly  straight,  prominent,  rounded  ridge. 

The  proximal  surface  of  the  bone  (figure  6)  shows  principally  the 
sub-triangular  saddle-shaped  face  for  articulation  with  the  ulna. 

The  distal  surface  of  the  bone  (figure  6)  presents,  also,  a  somewhat 
triangular  and  saddle-sliaped  face,  for  the  support  of  the  unciform  bone, 
and,  in  the  specimen  figured,  an  additional,  distinct,  oval,  and  convex  face, 
giving  support  to  the  metacarpal  of  the  fifth  digit. 

In  other  specimens,  this  face  is  present,  and  well  developed,  but 
confluent  with  that  supporting  the  uncifoi-m,  as  shown  in  the  woodcuts 
below,  figures  117  and  118. 


108 


DINOCERATA. 


The  pyramidal  bone  in  a  second  specimen  of  Binoceras,  and  in  one 
of  Tinoceras,  is  shown  in  figures  117  and  118,  below. 


Figure  117. — Left  |.yramidal  of  Tinoceras  ingens,  Marsh  (So.  1577} ;   distal  end. 
Figure  118. — Left  pyramidal  of  Dinoceras  mirahiU,  Marsh  (No.  1230);  distal  end. 
mcY.  face  for  fifth  metacarpal;  un.  face  for  unciform. 

Both  figures  are  one-half  natural  size. 


The  following  are  the  more  important  dimensions  of  the  pyramidal 
bone  in  three  specimens  of  Dinoceras  and  Tinoceras  : 


Measurements  of  Left  Pyramidal.     {Dinoceras  mirabile,  No.  1208.) 

m. 

Greatest  length  of  longitudinal  axis  of  pyramidal, ..  .045 

Total  length  of  bone, -  -  -  .098 

Least  transverse  diameter, .054 

Greatest  diameter  of  ulnar  articular  surface, .073 

Antero-posterior  diameter  of  ulnar  articular  surface, .049 

Greatest  diameter  of  articular  face  for  unciform, .064 

Antero-posterior  diameter  of  articular  face  for  unciform, .051 

Diameters  of  face  for  fifth  metacarpal, 01 8-.029 

Measurements  of  Left  Pyramidal.     [Dinoceras  mirahile,  No.  1230.) 

m. 

Greatest  length  of  longitudinal  axis  of  jjyramidal, .042 

Greatest  diameter  of  bone, .100 

Least  transverse  diameter, _. .062 

Greatest  diameter  of  ulnar  articular  face, ^ .083 

Antero-posterior  diameter  of  ulnar  articular  face, ..-. .(49 

Greatest  diameter  of  face  for  unciform, .067 

Antero-posterior  diameter  of  face  for  unciform, .05  7 

Diameter  of  face  for  fifth  metacarjjal, .020 


THE   FORE   FEET.  109 

Measurements  of  Left  Pyramidrd.     {Tinoceras  ingens.  No.  1577.) 

m. 

Greatest  length  of  longitudinal  axis  of  pyramidal, .050 

Greatest  diameter  of  bone, .113 

Least  transverse  diameter, . .069 

Greatest  diameter  of  ulnar  articular  surface, ._.    ._ .092 

Antero-posterior  diameter  of  ulnar  articular  surface,  .. ..    .062 

Greatest  diameter  of  articular  face  for  unciform, .080 

Antero-posterior  diameter  of  articular  face  for  unciform, 066 


The  Pisiform.     (Plate  XXXII,  figures  7-12.) 

The  pisiform  in  tlie  Binocerata  is  a  short,  stout  bone,  presenting,  as 
usual,  two  confluent  articular  faces,  one  for  the  ulna,  and  the  second  for 
the  pyramidal. 

Plate  XXXII,  figure  7,  represents  the  surface  of  the  pisiform  seen 
from  the  side  of  the  skeleton,  when  the  bone  is  in  its  natural  position, 
except  that  the  long  axis  has  been  placed  in  a  vertical,  instead  of  an 
oblique,  position.     Neither  of  the  articular  faces  can  be  seen  in  this  figure. 

The  inner  side  of  the  bone,  or  that  turned  toward  the  pyramidal 
(figure  8),  show^s,  at  its  proximal  end,  a  large  and  somewhat  triangular  face, 
flattened,  or  slightly  concave  or  convex,  and  extending,  in  the  specimen 
figured,  over  more  than  half  the  length  of  the  bone,  but,  in  some  specimens, 
it  is  proportionally  shorter. 

Figure  9,  which  gives  the  view  opposite  to  that  in  figure  7,  shows 
this  articular  face,  seen  obliquely. 

The  proximal  end  of  the  bone  (figure-  11)  is  nearly  covered  by  a 
triangular  articular  face  for  union  with  the  ulna.  This  face,  in  the 
specimen  figured,  is  flat  in  one  direction,  and  distinctly  convex  in  the 
other,  but  another  specimen  of  the  same  bone  has  this  face  distinctly 
convex  in  both  directions. 

Distally,  the  pisiform  is  strongly  roughened  and  tuberculated,  with 
the  end  rounded,  as  shown  in  figure  12. 

The  principal  measurements  of  two  specimens  of  the  pisiform  bone  in 
Dinoceras  mirahile  are  given  below. 


110  DINOCERATA. 

Measurements  of  Right  Pisiform.     (Dinoceras  mirabile,  No.  1211.) 

m. 

Length  of  pisiform  bone,  ._ — .061 

Greatest  transverse  diameter, .050 

Least  transverse  diameter, _ _.   —      .030 

Greatest  diameter  of  ulnar  articular  surface, _.    038 

Least  diameter  of  ulnar  articular  surface, .021 

Greatest  diameter  of  face  for  pyramidal, ... .047 

Least  diameter  of  face  for  pyramidal, .    -. .-     .029 

Measurements  of  Bight  Pisiform.     iDinoceras  mirabile,  No.  1620.) 

m. 

Length  of  pisiform  bone, .065 

Greatest  transverse  diameter, .045 

Least  transverse  diameter, -.  .033 

Greatest  diameter  of  ulnar  articular  surface, -. .042 

Least  diameter  of  ulnar  articular  surface, 021 

Greatest  diameter  of  face  for  pyramidal, .044 

Least  diameter  of  face  for  pyramidal, .023 


The  Trapezium. 

(Plate  XXXIII,  figures  1-6,  and  Plate,  LIV,  figure  1,  tm.) 

The  trapezium  in  the  Dinocerata  is  well  developed,  being 
considerably  larger  than  the  trapezoid.  It  presents  at  each  end  a  large 
articular  face,  and  a  third  smaller  and  much  less  regular  one,  for 
articulation  with  the  trapezoid,  on  tlie  side  turned  toward  that  bone. 

The  outer,  or  dermal,  surface  of  the  bone  (Plate  XXXIII,  figure  1), 
when  viewed  in  its  natural  position  in  the  foot,  is  rough  and  tuberculated. 
The  prsterior  view  (figure  2),  and  the  anterior  view  (figure  4),  likewise 
show  no  articular  faces.  Figure  3,  representing  the  surface  turned  toward 
the  trapezoid,  presents  an  irregular,  smooth  face  along  the  upper  margin. 
This  face  differs  in  size  and  proportions  in  different  specimens,  and  in  life 
moved  upon  a  corresponding  surface  on  the  trapezoid. 

The  proximal  end  of  the  bone  (figui'e  5)  is  almost  entirely  covered  by 
the  articular  face  for  the  scaphoid.  This  face,  nearly  semi-circular  in 
outline,  is  flattened  in  one  direction,  slightly  concave  in  the  other,  and 
confluent  along  the  straight  margin  with  the  face  for  the  trapezoid. 


THE   FORE   FEET.  Ill 

The  distal  end  (figure  6)  presents  a  semi-oval  articular  face,  not 
extending  quite  to  the  anterior  part  of  the  hone,  and  supporting  in  life  the 
well  developed,  short,  first  metacarpal.  This  articular  face  is  somewhat 
saddle-shaped,  being  convex  along  its  short  diameter,  and  slightly  concave 
lengthwise. 

The  main  dimensions  of  the  trapezia!  bone  in  two  specimens  of  the 
Dinocerata  are  given  below. 

Measurements  of  Left  Trapezium.     {Dinoceras  mirahile,  No.  1208.) 

m. 

Length  of  longitudinal  axis  of  trapezium, .036 

Greatest  horizontal  diameter,  __ .062 

Least  horizontal  diameter, .033 

Longest  diameter  of  proximal  articular  face, .04  4 

Transverse  diameter  of  proximal  articular  face, .026 

Longest  diameter  of  distal  articular  face, .048 

Transverse  diameter  of  distal  articular  face,    _..... .026 

Measurements  of  Right  Trapezium.     {Tirioeeras  ingens,lso.  1219.) 

m. 

Length  of  longitudinal  axis  of  trapezium,. .037 

Greatest  horizontal  diameter, .068 

Least  horizontal  diameter, ...  . .031 

Greatest  diameter  of  proximal  articular  face  (approximate), .  .045 

Transverse  diameter  of  proximal  articular  face, ...  .032 

Greatest  diameter  of  distal  articular  face,    _.._. .O.IS 

Transverse  diameter  of  distal  articular  face, .030 


The  Trapezoid. 

(Plate  XXXIII,  figures  7-12,  Plate  LIV,  figure  1,  tr  ,- 
and  woodcuts  119-120,   below.) 

The  trapezoid  is  a  small  bone  in  the  Dinocerata,  being  much  the 
smallest  of  the  carpals,  with  the  exception  of  the  pisiform,  and  perhaps 
also  of  the  central,  if  separate.  The  general  shape  of  the  bone  is  that  of 
a  blunt,  nearly  square,  wedge,  the  large  end  being  presented  to  the 
superior,  or  anterior,  surface  of  the  foot. 

This  end  of  the  bone  is  represented  in  Plate  XXXIII,  figure  7,  and 
shows  nearly  all  that  can  be  seen  of  it  when  in  its  natural  position  with 


112 


DINOCERATA. 


the  other  bones  af  the  foot.     The  surface  is  strongly  rugose,  and,  in  this 
view,  notliing  can  be  seen  of  the  articular  faces. 

The  lateral  surface  turned  toward  the  trapezium  presents  an  articular 
face  for  union  with  that  bone.  An  ordinary  form  of  this  face  is  shown 
in  figure  8,  but  it  is  of  variable  form  and  size.  Sometimes  it  even  extends 
obliquely  across  the  lateral  siu'face  of  the  bone,  and  becomes  more  or  less 
widely  confluent  with  the  articulation  for  the  metacarpal,  along  the 
anterior  paii  of  its  lateral  border,  as  in  woodcut  119   below. 

Fig.   120. 


Figure  1 19.  — LeI'l  trapezoid  of  Binoceras  miralile,  Marsh  (I^o.  1230);  side  view. 
FieUEF   120. — The  same  bone;   distal  end. 

mcJl.  face  for  second  metacarpal;  s.  face  for  scaphoid;  tm.  face  for  trapezium. 
Both  tigures  are  one-half  natural  size. 

The  posterior,  or  palmar,  aspect  of  the  bone  (figure  9)"  shows  its 
wedge-like  form,  but  the  articular  faces  visible  are  seen  only  obliquely. 

The  side  turned  tow^ard  the  magnum  (figure  10)  has  an  articular 
surface  extending  across  the  bone.  Usually,  this  surface  is  near  the 
anterior  part  of  the  bone,  and  sometimes,  as  in  the  specimen  figured,  is 
more  or  less  interrupted  at  the  middle  by  a  ridge.  This  surface  may 
also  be  broadly  continued  to  the  posterior,  or  palmar,  end  of  the  scaphoid 
articular  face,  as  in  number  1505. 

The  upper  ulnar  angle  of  this  specimen  is  rounded  for  articulation 
with  the  lunar.  This  portion  of  the  bone  may  represent  the  central, 
coalesced  with  the  trapezoid,  as  in  the  existing  Dendrohyrax. 

The  proximal  articular  face  (figure  11),  joining  the  scaphoid  bone,  is 
narrowly  oval  in  outline,  bi'oader  in  front  than  behind,  and  more  or  less 
concave  in  both  directions. 

The  distal  face  is  somewhat  similar  in  shape  to  the  proximal,  but 
sometimes  shorter  and  broader,  and  is  slightly  convex  in  one,  or  both 
directions. 


THE   FORE   FEET.  113 

The  principal  dimensions  of  the  trapezoid  bone  in  two  individuals  of 
Dinoceras,  and  one  of  Tinoceras,  are  as  follows : 

Measurements  of  Left   Trapezoid.     [Dinoceras  mirabile,  No.  1208.) 

m. 

Greatest  vertical  extent  of  trapezoid, .036 

Length  of  vertical  axis, - 022 

Greatest  (antero-posterior)  diameter, .058 

Transverse  diameter,  near  the  middle, . 029 

Antero-posterior  diameter  of  proximal  articular  face, .049 

Transverse  diameter  of  proximal  articular  face, . .027 

Antero-posterior  diameter  of  distal  articular  face, .051 

Transverse  diameter  of  distal  articular  face, 025 

Measurements  of  Left  Trapezoid.     (Dinoceras  mirabile,  l^o.  1230.) 

m. 

Greatest  vertical  extent  of  trapezoid, .034 

Length  of  vertical  axis, .023 

Greatest  (antero-posterior)  diameter, .      .067 

Transverse  diameter, .035 

Antero-posterior  diameter  of  proximal  articular  face, .050 

Transverse  diameter  of  proximal  articular  face, .029 

Antero-posterior  diameter  of  distal  articular  face, .043 

Transverse  diameter  of  distal  articular  face, .035 

Measurements  of  Right  Trapezoid.     (Tinoceras  ingens, 'No.  1219.) 

m. 

Greatest  vertical  extent  of  trapezoid, .038 

Length  of  vertical  axis, _..    ..    .. .025 

Greatest  (antero-posterior)  diameter, .068 

Transverse  diameter,  near  the  middle, ..    .033 

Antero-posterior  diameter  of  proximal  articular  face, .048 

Transverse  diameter  of  proximal  articular  face, .030 

Antero-posterior  diameter  of  distal  articular  face, _ 050 

Transverse  diameter  of  distal  articular  face, 029 


The  Magnum. 

(Plate  XXXIV,  figures  1-6,  Plate  LIV,  figure  1 ; 
and  woodcuts  121-122,  below.) 

The  magnum  in  the  Binocerata  is  proportionally  a  much  smaller  bone 
than  in  the  elephant,  and  has  a  much  greater  difference  in  the  length  of 
the  vertical  axis  in  the  anterior  and  posterior  parts  of  the  bone,  than 
in  that  animal. 

15 


114  DINOCERATA. 

An  anterior  view  of  the  magnum,  when  in  its  natural  position  among 
the  other  bones  of  the  carpus,  is  seen  in  Plate  XXXIV,  figure  1.  The 
dermal  surface  is  pentagonal  in  outline,  rough  and  tuberculated,  while 
behind  and  above  it,  is  seen  obliquely  a  portion  of  the  smooth  articular 
face  by  which  tlie  bone  articulates  Avith  tlie  lunar  and  scaphoid  bones  of 
the  preceding  carpal  series. 

The  lateral  surface  of  the  magnum  (figure  2)  turned  toward  the 
trapezoid  varies  in  the  shape  and  structure  of  its  articular  face  for  that 
bone.  This  face  is  frequently  more  or  less  divided,  as  in  the  specimen 
figured,  or  the  articular  face  may  be  on  the  distal  part  of  the  bone,  not 
extending  across  to  the  scaphoid  face.  A  large  proportion  of  the  posterior 
part  of  the  face  for  tlie  scaphoid  is  seen  in  the  same  figure.  This  face  is 
strongly  saddle-shaped.  In  the  same  view,  is  seen  a  third  articular  face, 
for  the  support,  in  part,  of  the  second  metacarpal.  This  face  is  narrow, 
arid  elongated  from  before  backward,  and,  in  the  natural  position  of  the 
bone,  is  directed  obliquely  downward,  towai'd  the  radial  side  of  the  foot. 

The  posterior,  or  palmar,  surface  of  the  magnum  (figure  3)  is  roug'h, 
but  rounded  over,  and  shows  at  the  upper,  or  proximal,  end  a  portion  of 
the  articular  face  for  the  lunar,  carried  well  over  on  the  posterior  face  of 
the  bone. 

The  lateral  surface  (figure  4)  turned  toward  the  unciform  presents 
a  considerable,  but  varving,  articular  surface  for  imion  with  that  bone. 
In  the  specimen  figured  (number  1208),  there  is  a  large  area  extending 
along  the  entire  length  of  the  proximal,  or  lunar,  articular  face,  contracting 
near  the  middle,  but  expanding  anteriorly,  so  as  to  extend  nearly,  or  quite, 
across  the  lateral  surface  of  the  bone.  In  many  specimens  (numbers 
1195,  1218,  1219,  1230,  1516),  this  area  is  confluent  with  the  distal  articular 
face  for  the  third  metacarpal.  In  the  specimen  figured,  however,  it  is, 
interrupted  by  a  slight  ridge  at  this  point,  beyond  which,  it  is  continued 
well  along  the  margin  of  this  articular  face  posteriorly.  This  distal 
backward  extension  of  the  articular  face  is  not  present  in  all  specimens 
(numbers  1195,  1230),  and  is  often  much  narrower  than  in  the  specimens 
figured  (numbers  1211,  1219) 


THE   FORE   FEET. 


115 


The  proximal  surface  of  the  magnum  (figm-e  5),  by  which  it  bears 
upon  the  scaphoid  and  lunar  bones,  is  much  elevated  posteriorly  in  the 
region  of  the  face  for  the  lunar,  but  the  two  facets  are  so  perfectly 
confluent  as  scarcely  to  be  distinguished.  The  face  for  the  scaphoid  is 
strongly  saddle-shaped,  and  does  not  extend  quite  to  the  anterior  margin 
or  the  bone. 

The  face  for  the  lunar  is  nearly  flat,  or  slightly  convex  from  side 
to  side,  sigmoid  from  before  backward,  and  is  carried  well  over  to  the 
posterior  face  of  the  bone.  The  variation  in  the  form  of  this  curve  is 
considerable,  but  the  specimen  figured  on  the  Plate  may  be  regarded  as  a 
fair  average,  while  extreme  forms  are  represented  in  woodcuts  121  and 
122,  below. 


iiu  //; 


Figure  121. — Right  magnum  of  Dinoceras  mirahile,  Marsh  (No.  1211);  aide  view. 
FieuRE  122. — Right  magnum  of  Dinoceras  mirahile,  (No.  1230);   side  view. 

I.  face  for  hmar;  mcIII.  face  for  third  metacarpal;  un.  face  for  unciform. 
Both  figures  are  one-half  natural  size. 


The  distal  face  of  the  magnum  (Plate  XXXIV,  figure  6)  is  mostly 
occupied  by  an  elongated  articular  face  for  the  support,  in  great  part,  of 
the  third  metacarpal.  This  face  is  more  or  less  moderately  concave  from 
before  backward,  slightly  convex  transversely,  and  is  usually  a  little 
broader  in  front  than  behind.  It  is  separated  by  a  rounded  ridge  from  the 
confluent,  narrower  and  oblique,  face  lying  along  its  radial  side,  and 
aiding  in  the  support  of  the  second  metacarpal. 

The  dimensions  of  the  magnum  bone  of  four  individuals  of  the 
Dinocerata  are  as  follows : 


116  DINOCERATA. 

Measurements  of  Left  Magnum.     (Dinoceras  inirabile.  No.  1208.) 

m. 

Length  of  longitudinal  axes  of  magnum, .033-062 

Antero-postei-ior  diameter-, 066 

Transverse  diameter, _. .     .038 

Anteio-posterior  diameter  of  proximal  articular  face, .-- .058 

Transverse  diameter  of  proximal  articular  face, -. .030 

Antero-posterior  diameter  of  face  for  second  metacarpal, .046 

Transverse  diameter  of  face  for  second  metacarpal, .  - .018 

Antero-posterior  diameter  of  face  for  third  metacarpal, .057 

Transverse  diameter  of  face  for  third  metacarpal, .     .025 

Measurements  of  Right  Magnum.     [Dinoceras  mirabile.  No.  1211.) 

m. 

Length  of  longitudinal  axes  of  magnum, - .036-069 

Antero-posterior  diameter,  ._. ^ .080 

Transverse  diameter, 039 

Antero-jjosterior  diameter  of  jjroximal  articular  face, .-     .0Y3 

Transverse  diameter  of  proximal  articular  face, : .032 

Antero-posterior  diameter  of  face  for  second  metacarpal, .060 

Transverse  diameter  of  face  for  second  metacarpal, _ 020 

Antero-posterior  diameter  of  face  for  third  metacari^al, 064 

Transverse  diameter  of  face  for  third  metacarpal, .027 

Measwements  of  Right  Magnum.     (Dinoceras  mirabile,  No.  1195.) 

m. 

Length  of  longitudinal  axes  of  magnum, 032-.062 

Antero-posterior  diameter, _. 063 

Transverse  diameter, _. .034 

Antero-jDosterior  diameter  of  proximal  articular  face, .065 

Transverse  diameter  of  proximal  articular  face, .027 

Antero-fiosterior  diameter  of  face  for  second  metacarpal, . .050 

Transverse  diameter  of  face  for  second  metacarjjal, .018 

Antero-posterior  diameter  of  face  for  third  metacarpal, :_ ._-.      .055 

Transverse  diameter  of  face  for  third  metacarpal, .022 

Measwements  of  Left  Magnum.     {Dinoceras  mirabile,  No.  1218.) 

m. 

Length  of  longitudinal  axes  of  magnum, .. 033'-.069 

Antero-posterior  diameter, .075 

Transveise  diameter, .041 

Antero-posterior  diameter  of  j)roximal  articular  face, .068 

Transverse  diameter  of  proximal  articular  face, ...      .034 

Antero-posterior  diameter  of  face  for  second  metacarpal,  ._ .049 

Transverse  diameter  of  face  for  second  metacarpal, .018 

Antero-posterior  diameter  of  face  for  third  metacarpal, . .063 

Transverse  diameter  of  face  for  third  metacarpal, .03 1 


THE   FORE  FEET.  117 

The  Unciform. 

(Plate  XXXIV,  figures  7-12,  Plate  LIV,  figure  1,  un  ; 
and  woodcuts  123-124,  below.) 

The  unciform  in  the  JDinocerata  is  similar,  in  general  shape  and 
proportions,  to  that  of  Proboscidians,  but  is  less  oblique,  and  presents  three 
sub-equal  articular  faces  on  its  distal  surface,  instead  of  two,  as  in 
the  elephant. 

The  exterior,  or  dermal,  surface  of  the  bone  (Plate  XXXIV,  figure  7) 
is  moderately  roughened  and  pitted,  and  is  regularly  rounded,  in  the 
horizontal  direction,  through  an  arc  but  little  short  of  a  quadrant.  From 
above  downward,  the  surface  is  nearly  plane. 

The  inner  surface  (figure  8),  or  that  turned  toward  the  magnum, 
is  bordered  above,  in  part,  and  partly  below,  by  a  smooth  articular 
face  for  union  with  that  bone.  The  amount  and  disposition  of  this 
surface  ^'ary  in  a  manner  corresponding  with  the  faces  for  its  union 
with  the  magnum,  as  before  described.  The  proximal  and  anterior 
portions  of  this  face  are  the  most  constant,  and  may  be  confluent  along 
the  whole  margin  of  the  proximal  articular  face,  or  mav  be  interrupted 
near  the  middle  (number  1195).  The  proximal  part  of  this  face  may 
extend  quite  across,  so  as  to  become  confluent  with  the  face  for  the  third 
metacarpal,  and  may  then,  as  in  the  specimen  figured,  border  that  face 
throughout  its  extent,  or  it  may  even  fail  to  reach  the  lower,  or  distal, 
margin  of  the  bone  at  all  (numbers  1509,  1525). 

The  posterior,  or  postero-interior,  face  of  the  unciform  (figure  9)  is 
quite  irregular,  and,  when  not  encroached  upon  by  articular  faces,  is 
moderately  roughened. 

The  outer  side  of  the  bone  (figure  10)  is  short  from  above  downward, 
allowing  the  articular  face  for  the  pyramidal  to  approach  that  for  the  fifth 
metacarpal,  as  in  the  elephant.  These  faces  may  even  be  confluent  for  a 
short  distance  across  this  surface  (number  1211),  as  in  figure  123,  below, 
or  may  be  separated  (numbers  1509  and  1525),  as  in  figure  124. 


118  DINOCERATA. 

The  proximal  face  (Plate  XXXIV,  figm-e  11)  is  obliquely  saddle- 
sliaped,  and  presents  two  confluent,  but  distinguishable,  faces,  one  for  the 
lunar,  and  one  much  larger,  for  the  pyramidal. 

The  face  for  the  lunar  lies  along  the  inner,  or  radial,  side  of  the 
proximal  surface,  and  is  sigmoid  from  before  backwards,  and  transversely 
more  or  less  convex.  Its  posterior  half  is  considerably  elevated  above 
the  anterior,  to  fit  into  a  corresponding  excavation  in  the  lunar. 

The  face  for  articulation  with  the  pyramidal  is  somewhat  in  the  form 
of  a  quadrant,  one  side  being  confluent  with  the  face  for  the  lunar,  the 
other  side  running  along  the  outer,  or  posterior,  margin  of  the  bone,  while 
the  curve  forms  the  upper  limit  of  the  dermal  surface.  This  face  is 
strongly  saddle-shaped,  concave  antero-posteriorly,  and  convex  from  side 
to  side. 

The  distal  surface  of  the  unciform  (figure  12)  bears  three  concave 
articular  faces  for  the  support  of  the  third,  fourth,  and  fifth  metacarpals. 
Of  these,  the  inner  is  the  smallest,  triangular  in  outline,  only  slightly 
concave,  and  aids  the  mag-num  in  the  support  of  the  middle,  or  third, 
metacarpal. 

The  second,  or  median,  articular  face  is  the  largest,  and  is  more 
deeply  concave  than  the  first.  It  extends  antero-posteriorly  quite  across 
tlie  distal  end  of  the  bone,  but  is  much  broader  in  front  than  behind. 
It  supports  the  fourth  metacarpal. 

Tlie  third  articular  face,  situated  upon  the  outer,  or  ulnar,  side  of 
tlie  distal  end  of  the  unciform,  is  more  strongly  concave  antero-posteriorly 
than  either  of  the  others,  and  is  nearly  as  broad  behind,  or  on  its  palmar 
margin,  as  in  front.  It  is  oblique  to  the  axis  of  the  bone,  and,  as  already 
mentioned,  may  even  be  confluent  for  a  short  distance  with  the  proximal 
face  for  the  pyramidal,  as  shown  in  figure  123,  below. 

The  unciform  bone  in  two  individuals  of  the  Blnocerata  is  represented 
in  the  woodcuts  below.  The  specimens  figured  show  marked  difi"erences, 
but  whether  these  are  constant  in  all  the  species  of  the  two  g-enera  cannot 
at  present  be  determined.     This  is  the  case,  also,  with  other  carpal  bones. 


THE   FORE   FEET, 


119 


Figure  123. — Right  unciform  of  Dinoceras  miraUle,  Marah  (No.  1211);  side  view. 
FiQ-UHE  124. — Right  unciform  of  Tinnceras  ingens,  Marsh  (No.  1509);   side  view. 
mcY.  face  for  fifth  metacarpal;  p.  face  for  pyramidal. 

Both  figures  are  one-half  natural  size. 

Four  specimens  of  tlie  unciform  bone  from  different  individuals  of 
Dinocerata  have  the  following  dimensions  : 

Measurements  of  Left  TJndfonn.     {Dinoceras  mirahile.  No.  1208.) 

m. 

Length  of  longitudinal  axes  of  unciform, .041-068 

Antero-posterior  diameter, __, .068 

Transverse  diameter, .086 

Antero-posterior  diameter  of  lunar  articular  face, .062 

Transvei'se  diameters  of  lunar  articular  face, ._ .020-.024 

Antero-posterior  diameter  of  face  for  pyramidal, 060 

Transverse  diameter  of  face  for  pyramidal, .     .055 

Antero-posterior  diameter  of  face  for  third  metacarpal, .05(1 

Transverse  diameter  of  face  for  third  metacarpal, .025 

Antero-posterior  diameter  of  face  for  fourth  metacarpal, .. .056 

Transverse  diameters  of  face  for  fourth  metacarpal, .. .021-.043 

Antero-posterior  diameter  of  face  for  fifth  metacarpal, .048 

Transverse  diameters  of  face  for  fifth  metacarpal, .020-.025 

Measurements  of  Right  Unciform.     {TDinoceras  mirahile, 'S.o.  1195.) 

m. 
Length  of  longitudinal  axes  of  unciform, OSS-.oe.") 

Antero-posterior  diameter, .067 

Transverse  diameter, ._.    .079 

Antero-posterior  diameter  of  face  for  lunar, .059 

Transverse  diameter  of  face  for  lunar, .019 

Antero-posterior  diameter  of  face  for  pyramidal, ..  .061 

Transverse  diameter  of  face  for  pyramidal, . . _.  .068 

Antero-posterior  diameter  of  face  for  third  metacarpal  (approximate), .052 

Transverse  diameter  of  face  for  third  metacarpal, .026 


120  DINOCERATA. 

m. 

Antero-posterior  diameter  of  face  for  fourth  metacarpal, .055 

Transverse  diameters  of  face  for  fourth  metacarpal, . .      .    .01 3-.044 

Antero-posterior  diameter  of  face  for  fifth  metacarpal, .041 

Transverse  diameter  of  face  for  fifth  metacarpal, .023 

Measurements  of  Right  Unciform.     [Divoceras  mirabile,  No.  1247.) 

m. 

Length  of  longitudinal  axes  of  unciform, ^ .046-073 

Antero-posterior  diameter, .-.  — .084 

Transverse  diameter,   .091 

Antero-posterior  diameter  of  face  for  lunar, . .070 

Transverse  diameter  of  face  for  lunar, .    ..  ._ .023 

Antero-posterior  diameter  of  face  for  pyramidal, .073 

Transverse  diameter  of  face  for  pyramidal,  _. .083 

Antero-posterior  diameter  of  face  for  third  metacarpal  (approximate), .  .     .057 

Transverse  diameter  of  face  for  third  metacarpal, .029 

Antero-posterior  diameter  of  face  for  fourth  metacarpal, .070 

Transverse  diameters  of  face  for  fourth  metacarpal, .    .019-.04S 

Antero-posterior  diameter  of  face  for  fifth  metacarpal, 055 

Transverse  diameter  of  face  for  fifth  metacarpal, 025 

Measurements  of  Right  Unciform.     {Tinoceras  i?igens, 'No.  1509.) 

m. 

Length  of  longitudinal  axes  of  unciform  (approximate), .051-.085 

Antero-posterior  diameter, .080 

Tranverse  diameter, ... --•. .098 

Antero-posterior  diameter  of  face  for  pyramidal  (approximate), _. .070 

'J'ransverse  diameter  of  face  for  pyramidal, .077 

Antero-posterior  diameter  of  face  for  third  metacarpal, .057 

Transverse  diameter  of  face  for  third  metacarpal, - .027 

Antero-posterior  diameter  of  face  for  fourth  metacarpal, -     .067 

Transverse  diameters  of  face  for  fourth  metacarpal, -.   .016-055 

Antero-posterior  diameter  of  face  for  fifth  metacarpal, ..     .056 

Transverse  diameter  of  face  for  fifth  metacarpal, 030 


The  Metacarpal  Bones. 

(Plates  XXXV,  XXXVI,  XXXVII,  and  Plate  LIV,   figure  1.) 

The  metacarpal  bones  in  tlie  JDinocerata  are  short  and  robust.  They 
are  five  in  number,  and  each  represents  a  well  developed  dig-it.  Their 
general  form  and  position  in  the  foot  of  Dinoceras  mirabile  are  shown  in 
Plate  LIV,  figure  1,  and  also  in  the  restoration  of  this  species,  Plate  LV. 


THE   FORE  FEET.  121 


The  First  Metacarpal.     (Plate  XXXV,  figures  1-6.) 

The  metacarpal  bone  of  the  first,  or  inner,  digit,  the  pollex,  is  a 
robust,  and  usually  short  bone,  proportionally  much  stronger  than  in 
the  elephant.  In  all  the  specimens  preserved,  the  epiphyses,  whether 
present  on  one  end  only,  or  on  both  ends,  as  in  the  elephant,  are  firmly 
coossified  with  the  shaft  of  the  bone.  The  surface  of  the  bone,  as  shown 
in  Plate  XXXV,  figures  1-4,  is  rough  and  very  irregular. 

The  proximal  articular  face  (figure  5)  is  nearly  elliptical  in  outline,  and 
is  flattened,  but  elevated,  near  the  middle  of  the  palmar  side  of  the  margin. 
On  some  specimens,  there  is  a  distinct  oval  face  for  contact  with  the 
second  metacarpal.  This  face  is  raised  upon  a  large  tubercular  elevation, 
and  may,  or  may  not,  be  in  contact  with  the  proximal  articular  face. 

The  distal  end  (figure  6)  presents  a  flattened,  and  somewhat  concave, 
face  for  the  phalangeal  bone,  and  two  broad,  oblique  grooves  for  the 
sesamoids. 

Three  first  metacarpals  of  JDinoceras  have  their  principal  dimensions 
as  follows : 

Measurements  of  First  Metacarpal.     {Dinoceras  mirabile,  No.  1208.) 

m. 
Total  length  of  first  metacarpal,  ._ .063 

Diameters  of  proximal  articular  face  (approximate), .025-.044 

Diameters  of  face  for  phalanx, 027— .034 

Measurements  of  First  Metacarpal.     [Dinoceras  tnirabile.  No.  1211.) 

m. 
Total  length  of  first  metacarpal, .098 

Diameters  of  j)roximal  articular  face  (approximate), .030-050 

Diameters  of  face  for  phalanx, .037-043 

Diameters  of  face  for  second  metacarpal,  _ ■_ .020-022 

Measurements  of  First  Metacarpal.     {Dinoceras,  No.  1526.) 

m. 

Total  length  of  first  metacarpal, .056 

Diameters  of  proximal  articular  face  (approximate), .026-044 

Diameter  of  face  for  phalanx, . .030 

16 


122  DINOCERATA. 

The  Second  Metacarpal.     (Plate  XXXV,  figures  7-12.) 

The  metacarpal  supporting  the  second  digit  in  the  Dinocerata  is 
nearly  twice  as  long  as  the  first,  but  not  greatly  wider,  nor  thicker.  The 
shaft  is  strongly  roughened  and  tuberculated  near  each  end,  as  shown  in 
Plate  XXXV,  figures  7-10,  while  the  middle  portion  is  much  smoother. 

The  proximal  end  of  the  bone  presents  three  distinct,  but  confluent, 
articular  faces,  of  which  the  first,  beginning  on  the  radial  side,  is  the 
largest.  It  met  the  trapezoid,  and  furnished  the  principal  support  of  that 
bone.  This  face,  shown  in  figure  11,  is  oblique  to  the  axis  of  the  bone, 
throwing  it,  in  its  natural  position,  well  toward  the  radial  side  of  the 
manus.  It  is  a  little  broader,  and  more  oblique,  above  than  below,  and  is 
slightly  concave  in  both  directions. 

A  second  adjoining  face,  shorter  and  smaller,  shown  also  in  figure  11, 
is  nearly  pei'pendicular  to  the  axis  of  the  bone,  slightly  narrowed  behind, 
and  convex  in  both  directions.  In  life,  this  face  articulated  with  the 
oblique  distal  face  of  the  magnum. 

A  third  face,  on  the  ulnar  side  of  the  bone  at  the  proximal  end,  shown 
best  in  figure  10,  articulated  with  a  similar  face  on  the  adjoining  third 
metacarpal. 

The  distal  end  of  the  bone  (figure  12)  bears  a  broadly  oval,  only 
slightly  convex,  articular  face  for  the  phalanx.  This  is  encroached  upon 
below,  by  the  broad,  shallow  grooves  for  sesamoid  bones. 

The  principal  dimensions  of  the  second  metacarpal  represented  in 
Plate  XXXV  are  as  follows  : 

Measurements  of  Second  Metacarpal.      {Dinoceras  mirabile,  No.  1208.) 

m. 

Total  length  of  second  metacarpal, _ .102 

Diameters  of  proximal  end, .039-.065 

Diameters  of  distal  end, .046-.0o8 

Diameters  of  shaft, _ .  _ 030-.040 

Antero-posterior  diameter  of  face  for  trapezoid, .050 

Transverse  diameters  of  face  for  trapezoid, ._ .020-023 

Antero-posterior  diameter  of  face  for  magnum, .046 

Transverse  diameters  of  face  for  magnum, __. 012-018 

Antero-posterior  diameter  of  face  for  third  metacarpal, ..  .040 

Diameters  of  face  for  phalanx,   025-.041 


THE  FORE   FEET.  123 

The  Third  Metacarpal.      (Plate  XXXVI,  figures  1-6.) 

The  third  metacarpal  resembles  the  second  m  general  size  and  shape, 
but  may  be  readily  distinguished  from  it  by  the  presence,  on  the  proximal 
end,  of  four,  instead  of  three,  articular  faces.  Like  that  bone,  it  is  rough 
and  tuberculated,  especially  near  the  ends.  It  bears,  also,  a,  rugose  surface 
not  far  above  the  middle  of  its  shaft  on  the  ulnar  side,  best  shown  in 
Plate  XXXVI,  figm-es  1  and  3. 

Of  the  four  proximal  articular  faces,  the  first,  beginning  on  the  radial 
side  is  almost  entirely  on  the  lateral  surface  of  the  bone,  as  represented 
in  figure  2.  In  life,  it  moved  upon  a  corresponding  face  on  the  adjoining- 
second  metacarpal.  It  is  confluent,  along  its  proximal  margin,  with  the 
second  articular  face,  which  is  the  largest  of  the  four,  and  articulated  with 
the  principal  distal  face  of  the  magnum. 

This  face,  shown  in  figures  2  and  5,  extends  with  parallel  sides  across 
the  proximal  end  of  the  bone,  from  before  backward.  It  is  concave 
from  side  to  side,  though  slightly  convex  antero-posteriorly,  and  formed, 
during  life,  the  principal  support  of  the  bone.  Its  plane  is  more  inclined 
to  the  axis  of  the  bone  than  is  that  of  the  third  face,  which,  in  life,  rested 
on  the  unciform. 

The  third  face,  best  shown  in  figure  5,  is  large  and  triangular,  the 
apex  of  the  triangle  being  turned  posteriorly,  or  toward  the  palmar  surface 
of  the  manus.  This  face  articulated  with  the  unciform.  It  is  convex  in 
both  directions,  and,  being  more  nearly  perpendicular  to  the  axis  of  the 
metacarpal  than  is  the  face  for  the  magnum,  must  have  contributed, 
during-  life,  nearly  as  much  to  its  support. 

The  face  for  the  unciform  is  confluent  along  its  entire  outer,  or  ulnar, 
margin  with  a  fourth,  broad  articular  face  on  the  side  of  the  bone  (figure  4), 
which,  in  life,  met  a  corresponding  face  on  tlie  fourth  metacarpal. 

The  distal  end  of  the  bone  (figure  (!)  supports  a  moderately  convex 
face  for  the  ])1ialangeal  articulation,  placed  well  upon  the  upper  surface  of 
the  bone,  and  scarcely  extending  as  low  as  the  middle  of  the  distal  end. 
Here,  it  is  met  by  the  broad  and  shallow  grooves,  in  which  a  pair  of 


124  DINOCERATA. 

sesamoid  bones  moved  dm-ing-  life.     The  ridge  between  these  grooves  is 
nearly  obsolete  in  front,  but  well  developed  posteriorly. 

The   more    important   measurements    of   two    third    metacarpals    of 
Dinoceras  are  given  below. 

Measurements  of  Third  Metacarpal.      [Dinoceras  tnirabile,  No.  1208.) 

m. 

Total  length  of  third  metacarpal, .114 

Diameters  of  proximal  end, ._. 052-062 

Diameters  of  distal  end, ... .044-054 

Diameters  of  shaft, .031-042 

Anlero-posterior  diameter  of  face  for  second  metacarpal, . .040 

Transverse  diameter  of  face  for  second  metacarpal, .. .015 

Antero-posterior  diameter  of  face  for  magnum, .,      .056 

Transverse  diameter  of  face  for  magnum, .022 

Antero-posterior  diameter  of  face  for  unciform, ._.   .050 

Transverse  diameter  of  face  for  unciform, .030 

Antei-o-posterior  diameter  of  face  for  fourth  metacarpal, _..      .050 

Transverse  diameter  of  face  for  fourth  metacarpal, ,     .025 

Diameters  of  face  for  phalanx, .0-'5-.042 

Measurements  of  Third  Metacarpal.     [Dinoceras  mirablle,  No.  1529.) 

m. 

Diameters  of  proximal  end  of  third  metacarpal, . .044-.073 

Diameters  of  shaft, .032-.040 

Antero-posterior  diameter  of  face  for  second  metacarpal, .043 

Transverse  diameter  of  face  for  second  metacarpal, .014 

Antero-posterior  diameter  of  face  for  magnum, ■ .069 

Transverse  diameter  of  face  for  magnum, ...    .OQo 

Antero-posterior  diameter  of  face  for  unciform  (approximate), . .' . .     .055 

Transverse  diameter  of  face  for  unciform, _.  ..     .030 

Antero-posterior  diameter  of  face  for  fourth  metacarpal, 059 

Transverse  diameter  of  face  for  fourth  metacarpal, .015-.018 


The  Fourth  Metacarpal. 

(Plate  XXXVI,  figures  7-9,  and  Plate  XXXVII,  figures  1-3.) 

The  fourth  metacarpal  in  the  Dinocerata  is  a  robust  bone,  like  the 
second  and  third  of  the  series.  It  may  be  easily  distinguished  by  the 
broad,  sub-triangular,  convex  articular  face,  at  right  angles  with  the  axis  of 
the  bone,  and  covering  its  entire  proximal  end. 


THE   FORE  FEET.  125 

The  surface  of  tlie  bone  is  roughened  towards  the  ends,  but  smoother 
along  tlie  shaft,  as  shown  in  Plate  XXXVI,  figures  7  and  8,  and  Plate 
XXXVII,  figures  1  and  2.  It  is  considerably  extended  antero-posteriorly 
near  the  proximal  end,  but  is  constricted  at  tlie  middle. 

The  proximal  end  (Plate  XXXVII,  figure  3)  is  almost  completely 
covered  by  the  articular  face  for  the  unciform  bone,  by  which  the  fourth 
metacarpal  was  entirely  supported.  This  face  is  convex  in  both 
directions,  and  broad  in  front.  It  becomes  much  narrower  behind,  or 
toward  the  palmar  side  of  the  manus,  so  as  to  appear  triangular,  but  does 
not  come  quite  to  a  point.  Along  each  side,  it  is  confluent  with  narrow 
faces,  nearly  at  right  angles  with  the  main  surface,  which  joined,  during 
life,  corresponding  faces  on  the  third  and  fifth  metacarpals. 

The  largest  of  these  lateral  faces,  shown  in  Plate  XXXVI,  figure  8, 
extends  along  the  entire  margin  of  the  unciform  face  on  its  radial  side, 
and  was  adapted  to  the  third  metacarpal. 

On  the  opposite,  or  ulnar,  side  (Plate  XXXVII,  figure  2),  a  smaller 
and  shorter  face,  sometimes,  as  in  the  specimen  figured,  much  larger 
anteriorly,  was  adapted,  during  life,  to  the  fifth  metacarpal. 

The  distal  end  of  the  bone  (Plate  XXXVI,  figure  9)  presents  a 
rounded,  and  but  slightly  convex,  face  for  the  phalanx,  and  below  are 
shallow  grooves  for  the  two  sesamoid  bones. 

Measurements  of  the  fourth  metacarpal  bone  in  four  specimens  of 
the  Binocerata  are  as  follows  : 

Measurements  of  Fourth  Metacarpal.     {Dinoceras  mirabile,  No.  1211.) 

m. 

Total  length  of  fourth  metacarpal, .131 

Diameters  of  proximal  end, .050-081 

Diameters  of  distal  end, .052-044 

Diameters  of  shaft  (aj^proximate), 0.38-.041 

Antero-posterior  diameter  of  face  for  unciform, .076 

Transverse  diameters  of  face  for  unciform,    ,-. .022-048 

Antero-posterior  diameter  of  face  for  third  metacarpal, .062 

Transverse  diameters  of  face  for  third  metacarpal, .013-022 

Antero-posterior  diameter  of  face  for  fifth  metacarpal, .052 

Transverse  diameters  of  face  for  fifth  metacarpal, . .060-022 

Diameters  of  face  for  phalanx, . .035-.040 


126  DINOCERATA. 


Measurements  of  Fourth  Metacarpal.     {Dinoceraa  lucare,  No.  1038.) 

m. 

Total  length  of  fourth  metacarpal, .117 

Diameters  of  proximal  end, 047-.064 

Diameters  of  distal  end, 054-.041 

Diameters  of  shaft  (approximate), . 027-.039 

Antero-posterior  diameter  of  articular  face  for  unciform  (approximate), .060 

Transverse  diameters  of  articular  face  for  unciform  (approximate), 021-040 

Antero-posterior  diameter  of  articular  face  for  third  metacarpal  (app)roximate) , .050 

Transverse  diameters  of  articular  face  for  third  metacarpal  (approximate),  _  .    _.. 012-020 

Antero-posterior  diameter  of  articular  face  for  fifth  metacarpal, .042 

Transverse  diameters  of  articular  face  for  fifth  metacarpal  (approximate),  - .  _    -  ..080-.018 
Diameters  of  articular  face  for  phalanx, 032— .042 


Measurements  of  Fourth  Metacarpal.     (Dhioceras,  No.  1523.) 

m. 

Total  length  of  fourth  metacarpal, _ .096 

Diameters  of  proximal  end  (approximate), 040-.061 

Diameters  of  distal  end, 045-.034 

Diameters  of  shaft  (approximate), 020-.033 

Antero-posterior  diameter  of  articular  face  for  unciform, .058 

Transverse  diameter  of  articular  face  for  unciform, .040 

Antero-posterior  diameter  of  articular  face  for  fifth  metacarpal, —  . .     .042 

Transverse  diameters  of  articular  face  for  fifth  metacarpal, 040-.01 7 

Diameters  of  articular  face  for  phalanx, 023-039 


Measurements  of  Fourth  Metacarpal.     {Tinoceras  ingens,  No.  1219.) 

m. 

Total  length  of  fourth  metacarpal, ._ .117 

Diam.eters  of  jjroximal  end, -. 054-.071 

Diameters  of  shaft  (approximate), 028-.040 

Antero-posterior  diameter  of  articular  face  for  unciform, .064 

Transverse  diameter  of  articular  face  for  unciform  (approximate), .048 

Antero-posterior  diameter  of  articular  face  for  third  metacarpal, . .055 

Transverse  diameters  of  articular  face  for  third  metacarijal, 014-019 

Antero-posterior  diameter  of  articular  face  for  fifth  metacarpal, _.     .047 

Transverse  diameter  of  articular  face  for  fifth  metacarpal, .020 

Diameters  of  articular  face  for  phalanx, ._ 030-.042 


THE  FORE  FEET.  127 


The  Fifth  Metacarpal.     (Plate  XXXVII,  figures  4-9.) 

The  specimens  of  the  fifth  metacarpal  in  the  Yale  Museum  are, 
unfortunately,  all  more  or  less  distorted  by  pressure,  and  hence  fail  to 
fully  represent  this  element  of  the  manus.  The  bone  is  well  developed, 
scarcely  smaller  than  the  third  and  fourth,  and  considerably  surpasses  the 
first  in  length.  Like  the  other  bones  of  the  metacarpal  series,  it  is  rough 
and  tubercular,  especially  toward  the  ends. 

The  proximal  end  (Plate  XXXVII,  figure  8)  presents  three  articular 
faces,  of  which  the  main  and  middle  one,  for  the  support  of  the  bone  upon 
the  unciform,  is  strongly  convex.  The  convexity  is  carried  tlirough  a 
considerable  arc  in  the  antero-posterior  direction,  to  correspond  with  the 
outer,  and  most  concave  facet,  on  the  unciform  bone,  to  which  it  is  adapted. 
This  surface  is  bordered,  on  the  inner,  or  radial  side,  by  a  face,  broadest 
anteriorly,  for  motion  on  the  fourth  metacarpal.  Behind,  and  on  the  outer, 
or  ulnar,  side  of  the  principal  articular  face,  is  a  much  smaller  face,  which, 
in  life,  moved  upon  a  corresponding  articulation  on  the  distal  end  of  the 
pyramidal. 

In  some  specimens,  the  shape  of  the  unciform,  as  shown  on  page 
119,  figure  124,  would  seem  to  make  this  impossible,  and  doubtless  this 
face  will  not  be  found  to  be  constantly  present  on  the  fifth  metacarpal. 

The  distal  end  of  the  bone  (Plate  XXXVII,  figure  9)  presents,  as 
usual,  a  round,  or  oval,  face  for  articulation  with  the  phalanx,  and  shallow 
grooves  below  for  a  pair  of  sesamoids. 

The  specimens  preserved  are  so  much  distorted  that  measurements 
would  be  of  comparatively  little  value. 


The  Phalanges.     (Plate  XXXVIII,  and  Plate  LIV,  figure  1.) 

The  phalanges  in  the  fore  foot  of  the  Dinocerata  are  very  short,  and 
comparatively  small.  Their  general  characters  are  shown  in  the  Plates 
cited  above,  as  well  as  in  the  restorations  given  in  Plates  LV  and  LVI. 


128  DINOCERATA. 

The  proximal  phalanges  (Plate  XXXVIII,  figures  1  and  2)  are  much 
the  largest.  The  proximal  surface  has  no  central  groove,  and  is  adapted 
to  the  comparatively  smooth  face  on  the  distal  end  of  the  metacarpals. 

The  median  phalanges  (figures  3  and  4)  are  much  shorter  than  those 
described  above.  Their  proximal  articular  faces  are  nearly  flat,  and  the 
distal  ones,  smaller,  and  more  concave  transversely. 

The  ungual  phalanges  (figures  5  and  6)  are  larger  than  those  of  the 
median  series,  and,  with  the  exception  of  the  small  articular  face,  their 
surfaces  are  very  rugose. 


CHAPTER    IX. 


THE   RIBS  AND   STERNUM. 
(Plates  XXXIX,  XL,  LV,  and  LVI.) 
The  ribs  in  the  Dinocerata  present  no  special  characters  of  importance. 
Their  general  features  are  well  shown  in  tlae   illustrations  above   cited, 
especially  in  the  restorations  at  the  end  of  the  volume. 

The  Fiest  Rib. 
(Plate  XXXIX,  figures  1-3.) 

The  first  rib  in  the  Dinocerata  has  a  general  resemblance  to  the 
corresponding  bone  in  the  mastodon.  It  is,  however,  jjroportionally 
shorter,  and  more  flattened  at  the  sternal  end. 

This  rib  presents  a  well  rounded  articular  face  to  the  first  dorsal 
vertebra,  and,  confluent  with  this,  on  the  anterior  side  of  the  head,  is 
another  strongly  convex  face,  for  articulation  with  a  well  developed  facet 
near  the  posterior  margin  of  the  last  cervical  vertebra. 

The  tubercular  articulation  is  but  little  elevated  above  the  capitular. 
It  is  convex  from  before  backward,  concave  from  side  to  side,  and  looks 
almost  perpendicularly  upward,  being  directed  but  very  slightly  backward. 
The  tubercle  of  the  rib  extends  outward  beyond  the  articular  face. 

The  shaft  is  moderately  roughened,  more  especially  on  its  anterior, 
or  outer,  surface.  The  sternal  face  is  so  strongly  flattened  and  expanded 
that  the  external  border  of  the  rib  shows  only  a  very  moderate  degree  of 
curvature.  The  inner  border,  however,  is  strongly  curved,  mostly  in  the 
upper  half  of  the  bone. 

17  129 


130 


DINOCERATA. 


The  Anterior  Dorsal  Ribs.      (Woodcuts  125-132,  below.) 
The  second  rib  in  one  species  of  Uintatherium  is  represented  in  the 


figures  belo^A^ 

Fig.  12r> 


Figure  125. — Second  rib  of  Uintatherium  latifrons,  Marsh  (No.  1231^;  posterior  view. 
Figure  126. — The  same  rib;  front  view. 
Figure  127. — The  same  rib  ;  inner  view. 
FlGUBE  128. — The  same  rib  ;  proximal  end. 
h.  head  ;  t.  tubercle. 

All  tlie  figures  are  one-fourth  natural  size. 

The  second  rib  is  much  longer,  and  less  robust,  than  the  first,  above 
described.  The  head  is  large,  and  the  two  articular  faces  on  it  are 
confluent.  The  tubercle  is  well  developed,  and  at  nearly  the  same  level 
as  the  head.  The  shaft  is  only  moderately  curved,  and  considerably 
compressed.     The  distal  end  is  flattened,  and  wider  than  the  shaft. 


THE  RIBS  AND  STERNUM. 


131 


The  ribs  behind  the  second  gradually  increase  in  length,  and  become 
more  cm-ved.  The  head  remains  large,  and  its  articular  faces  are  usually 
separated  from  each  other,  as  shown  in  figures  129-132,  below. 


\  \ 


FlGtTRE  129. — Anterioi'  rib  of  Binoceras  mirabile,  Marsh  (No.  1212);   postfirior  view. 
Figure  13U. — Tlie  same  rib:   inner  view. 
Figure  131. — The  same  rib;  front  view. 
Figure  132. — Tlie  same  rib;  proximal  end. 
h.  head;   t.  tubercle. 

All  the  figures  are  one- fourth  natural  size. 


132  DINOCERATA. 

The  main  dimensions  of  the  first  rib  in  one  individual  of  Dinoceras 
mirahile  are  as  follows : 

Measurements  of  First  Rib.     {Dinoceras  mirahile,  No.  1251.) 

m. 

Total  length  of  rib, .320 

Greatest  diameter  of  head, .. .038 

Transverse  diameter  of  head,  •_ .032 

Diameters  of  tubercular  articulation, .020-030 

Diameters  of  shaft,  near  the  middle, 021-040 

Diameters  of  shaft,  at  sternal  end, 027-095 

The  principal   measm-ements  of  the  second  rib   of  Uintatheriiim  are 
given  below. 

Measurements  of  Second  Mib.     {Uintatherium  latifrons.  No    1231.) 

m. 

Total  length  of  rib,  in  straight  line,   _-    ... ..... ..     .440 

Greatest  diameter  of  head, .055 

Transverse  diameter  of  head, _.     .030 

Diameter  of  tubercular  articular  face, .. . .024 

Diameters  of  shaft,  near  the  middle,  .. .020-.039 

Diameters  of  shaft,  at  lower  end  (approximate), _ .025-.060 

The  dimensions  of  two  dorsal  ribs  of  Dinoceras  are  as  follows : 

Measurements  of  Anterior  Rih.     [Dinoceras  mirabile, 'So.  1212.) 

m. 

Total  length  of  rib,  in  straight  line, ,500 

Greatest  diameter  of  head, : .048 

Transverse  diameter  of  head, — .036 

Diameter  of  tubercular  articular  face  (approximate),  .. —    ..    ..    —     .023 

Diameters  of  shaft,  near  the  middle,..,. _. .022-060 

Diameters  of  shaft,  at  lower  end  (approximate), — .025-038 

Measurements  of  Median  Rib.     [Dinoceras  mirahile,  No.  1210.) 

m. 

Total  length  of  rib,  in  a  straight  line, .605 

Diameters  of  head, .047-.ii58-.0U5 

Diameters  of  neck, .034-.039 

Diameters  of  shaft, .017-057 


THE  RIBS  AND  STERNUM.  133 

The  Posterior  Ribs.     (Plate  XXXIX,  figures  4-9.) 

The  posterior  ribs  gradually  diminish  in  length,  and  become  more 
slender,  but  the  curvature  is  still  strongly  marked.  In  most  of  them,  the 
head  is  large,  and  the  two  articular  faces  on  it,  distinct.  The  tubercle 
diminishes  in  size,  and  toward  the  last  is  a  mere  sessile  articular  face. 

The  sternal  ribs  are  not  preserved  in  any  of  the  known  specimens  of 
the  Dinocerata,  and  they  were  probably  unossified.  Their  general  form 
and  position  are  indicated  in  the  restorations,  Plates  LV  and  LVI. 

The  more  important  dimensions  of  two  posterior  ribs  in  the  type  of 
Binoceras  mirabile  are  the  following  : 

Measurements  of  Dorsal  Rib.     (Dinoceras  tnirabile.  No.  1036.) 

m. 

Totnl  length  of  rib,  in  straight  line, .530 

Greatest  diameter  of  head, .. _    ._.__     .052 

Transverse  diameter  of  head, .037 

Least  diameter  of  shaft,  near  the  middle, .015 

Diameters  of  shaft,  at  broadest  point, ..   025-.060 

Measurements  of  Posterior  Rib.     {^Dinoceras  mirabile.  No.  1036.) 

m. 

Total  length  of  rib,  in  straight  line, ...    520 

Greatest  diameter  of  head, .056 

Transverse  diameter  of  head, __    .062 

Diameters  of  shaft,  at  broadest  point, .016-051 


The  Sternum. 

(Plate  XL;  and  woodcut  133,  below.) 

Sternal  bones  are  preserved  in  a  number  of  individuals  of  the 
Dinocerata  in  the  Yale  Museum,  but  the  entire  series  in  any  one 
individual  has  not  been  recovered.  The  general  form  and  character  of 
these  bones  are  shown  in  the  figures,  Plate  XL.  A  series  in  the  natural 
position  is  represented  in  the  woodcut  below. 


134 


DINOCERATA. 


The  most  marked  charactev  of  these  bones  in  the  Dlnocerata  is  that 
they  are  flat  and  horizontal,  as  in  the  Artiodactjds,  and  not  vertical,  as  in 
the  Proboscidians,  and  the  Perissodactyls.  The  first  bone  of  the  series,  or 
the  pre-sternum,  is  compressed,  pointed  in  front,  and,  at  this  end,  has  two 
distinct  facets  for  the  first  pair  of  ribs.  This  bone  is  shown  in  Plate  XL, 
figu]-es  1,  2,  and  3. 

Tlie  bones  which'  follow,  and  compose  the  meso-sternum,  are  broad 
and  flat,  somewhat  constricted  near  the  middle,  with  the  ends  more  or 
less  convex.  The  anterior  ends  are  usually  strongly  convex,  while  the 
posterior  exti'emities  may  be  nearly  flat. 

Two  examples  of  these  median  sternal  bones  are  shown  in  the  same 
Plate,  figures  4-9,  as  well  as  in  the  woodcut  below. 


Figure  133. — Sternum  of  Dinoceras  mirahile,  Mnrsb;  top  view. 

One-fifth  natural  size. 

The  last  sternal  bone  of  the  series,  or  tlie  xiphi-sternum,  is  also  broad 
and  flat,  but  has  tlie  posterior  extremity  pointed.  This  bone  is  shown  in 
figures  10-12,  of  the  same  Plate. 

The  surface  of  all  the  sternal  bones  is  quite  i-ugose,  and  tlie 
extremities  are  deeply  pitted  for  union  with  tlie  cartilage  that  held  them 
in  position. 

No  indication  of  clavicles  lias  been  observed. 


CHAPTER    X. 

THE   PELVIC   ARCH  AND   TAIL. 
(Plates  XLI,  XLII,  XLIII,  LV,  and  LVI.) 

The  Pelvis. 
(Plates  XLI-XLII ;  and  woodcuts  134-135,  below.) 

In  all  the  known  specimens  of  the  Dinocerata  in  which  the  pelvic 
arcli  is  preserved,  the  ilium,  ischium,  and  pubis  are  firmly  coosified  with 
each  other,  but  not  with  the  sacrum.  The  three  pelvic  bones  on  each 
side  unite  with  each  other  eai-lier,  and  much  more  closely,  than  they  do 
with  the  sacrum  above,  or  with  the  opposite  pelvic  bones  below.  The 
sutures  for  the  latter  union  remained  open  until  the  animal  was  fully  adult, 
and,  even  then  in  some  specimens,  were  readily  separated.  These 
features  are  well  shown  in  Plate  XLI. 

The  pelvis  of  Binoceras  may  be  compared  with  that  of  the  elephant, 
to  which  it  bears  a  considerable  resemblance,  but  from  which  it  differs  in 
many  important  particulars. 

The  ilia  are  much  expanded,  and  nearly  quadrant-shaped  in  outline, 
the  supra-iliac  border  being  very  regularly  curved,  and  only  moderately 
thickened  near  its  union  with  the  acetabular  border,  which  it  joins  at  about 
a  right  angle.  The  iliac  surface  is  moderately  concave  in  both  directions, 
especially  near  the  surface  for  union  with  the  sacrum. 

The  gluteal  surface  is  nearly  flat  where  most  expanded,  but  becomes 
convex  in  the  acetabular  region.  It  rises  but  little  above  the  sacral 
articular    surface,    which   is    short,  somewhat   triangular   in    outline,    and 


136 


DINOCERATA. 


presents  a  strong  union  with  the  transverse  processes  of  the  first  two  sacral 
vertebrae. 

The  ilia  are  more  rounded  in  outline,  and  tlie  puhes  are  less  firmly 
united  at  the  symphysis,  than  in  the  mastodon.  The  ischia,  also,  do  not 
unite  at  all,  as  in  that  animal,  but  are  rounded  off,  and  distant  from 
each  other. 

Fig.  134. 


Figure   134. — Pelvis  of   Tinoceras  ingens,  Mavsii  (So.  1-197);   sceu  f'loiu  bulow. 


Figure  135. — The  same;  front  Mew 

a.  aeetabiihiui ;    /.   thyroid   foramen;    il   ilium;    is.   ischium;    ^>.  pubis;    s.   anterior  end  of  sacrum; 
6'.  posterior  end  of  sacrum. 

Both  fiKures  are  one-cii'hlh  natural  size. 


THE  PELVIC  ARCH  AND  TAIL.  137 

The  pelvic  arch  in  Tinoceras  is  similar,  in  its  general  featui'es,  to  that 
of  Dinoceras,  but  presents  various  differences  which  are  apparent  in 
comparing  the  figures  134  and  135,  above,  with  the  corresponding  views 
of  the  type  specimen  of  Dinoceras  mirahile  represented  in  Plate  XLI. 

The  sacrum  in  Dinoceras  differs  from  that  of  Mastodon  Americanus  in 
having  four  sacral  vertebrae  instead  of  five,  and  much  larger  transverse 
processes,  for  articulation  with  the  ilia.  The  foramina  between  these 
processes  are  also  proportionally  much  larger.  Only  the  first  two  of  the 
processes  unite  strongly  with  the  ilium,  instead  of  four,  as  in  the  mastodon. 
Both  the  sacrum,  and  the  face  for  attachment  to  the  ilium,  are 
proportionally  much  shorter  than  in  the  mastodon. 

The  more  important  dimensions  of  the  pelvic  arch  in  the  type 
sj^ecimen  of  Dinoceras  mirahile,  and  in  one  individual  of  Tinoceras  ingens, 
are  the  following : 

Measurements  of  Pelvis.     [Dinoceras  mirable.  No.  1036.) 

m. 

Greatest  transverse  diameter,  across  ilia, 1.120 

Horizontal  diameter  of  pelvic  opening  (approximate), .350 

Vertical  diameter  of  pelvic  opening  (approximate), .250 

Diameter  across  acetabula, ._ .660 

Diameters  of  acetabulum, ..i .110-.  125 

Diameters  of  thyroid  foramen, ..-. .   .075-.  150 

Length  of  symphysis  pubis, ... ._.      .140 

Length  of  four  sacral  vertebra}  (approximate), .245 

Extent  of  transverse  processes  of  first  sacral, - -      .330 

Horizontal  diameter  of  anterior  face  of  first  sacral, .110 

Vertical  diameter  of  anterior  face  of  first  sacral, .075 

Length  of  first  sacral  centrum, ._ 075 

Measurements  of  Pelvis.     [Tinoceras  ingens,  No.  1497.) 

m. 

Greatest  transverse  diameter,  across  ilia, 1.180 

Horizontal  diameter  of  pelvic  opening  (approximate), .     .400 

Vertical  diameter  of  pelvic  opening  (approximate), .300 

Diameter  across  acetabula, .. .700 

Diameters  of  thyroid  foramen, -_ .060—  150 

Length  of  symphysis  pubis, •_ .140 

Length  of  four  sacral  vertebrae, _ _. ._.      .295 

Extent  of  transverse  processes  of  first  sacral, .355 

Horizontal  diameter  of  anterior  face  of  first  sacral, ., .117 

18 


138  DINOCERATA. 

m. 

Vertical  diameter  of  anterior  face  of  first  sacral, .-. -072 

Length  of  centrum  of  first  sacral, __. .085 

Length  of  centrum  of  second  sacral, .O'ZS 

Length  of  centrum  of  third  sacral, . .065 

Length  of  centrum  of  fourth  sacral, . .067 


The  Caudal  Vertebra. 
(Plate  XLIII ;    and  woodcut  136,  below.) 

The  anterior  caudal  vertebrae  of  the  Dinocerata  have  the  centra  short 
and  flat,  with  long  and  depressed  transverse  processes.  The  neural  spine 
is  only  moderately  developed.  The  neural  arch  is  low,  and  situated  on 
the  anterior  two-thirds  of  the  centra.  The  zygapophyses  are  weak,  and 
their  articular  faces  usually  curved. 

In  the  median  caudals,  the  transverse  processes  become  shorter,  and 
gradually  disappear. 

The  distal  caudals  are  cylindrical,  and  of  moderate  length.  They 
are  without  zygapophyses,  or  neural  arches,  as  seen  in  figure  136,  below. 


Figure  136. — Caudal  vertebra  of  Dinoceras  laticeps,  Marsh  (No.  1039). 
a.  proximal  end;   6.  side  view;  c.  distal  end. 

All  the  figures  are  one-half  natural  size. 


The  under  surface  of  the  caudal  vertebrae  is  rugose,  and  there  are 
no  chevron  bones. 


CHAPTER    XL 


THE    HIND    LIMBS. 

(Plates  XLIV,  XLV,  XLVI,  LV,  and  LVI.) 

The  hind  Hmbs  of  the  Dinocerata  have  a  general  resemblance  to  those 
of  Proboscidians,  but  the  bones  composing'  them  are  comparatively 
shorter,  and  more  robust.  When  the  animal  was  standing  at  rest,  the 
posterior  limb  formed  a  strong  and  nearly  vertical  column.  The  contrast 
in  this  respect  between  the  hind  and  the  fore  limb  has  already  been  stated, 
in  the  description  of  the  latter  in  Chapter  VII. 


The  Femur.     (Plate  XLIV;  and  woodcuts  137-138,  below.) 

The  femur  in  the  Dinocerata  is  proportionally  shorter  than  in  the 
elephant.  It  is  much  smoother  throughout  than  the  humerus,  and  is  also 
somewhat  longer  than  that  bone. 

The  head  of  the  femur  is  hemispherical,  and  its  axis  makes  an  angle 
of  about  fifteen  degrees  with  the  axis  of  the  shaft  of  the  bone.  The 
diameter  of  the  head  is  contained  about  five  and  one-half  times  in  the 
length  of  the  femur.     There  is  no  indication  of  any  pit  for  the  round 

139 


140  DIXOCEHATA. 

ligament,  as  is  seen  in  Plate  XLIV,  figure  3  a.  The  great  trochanter 
scarcely  rises  above  the  base  of  the  head.  It  is  flattened,  and  posteriorly 
is  excavated  below. 

The  upper  end  of  the  shaft  is  broad,  flattened  in  a  fore  and  aft 
direction,  and  is  excavated  behind,  especially  below  the  great  trochanter. 
It  contracts  in  transverse  diameter  gradually  to  a  minimum,  near  the 
middle  of  the  shaft,  and  just  below  the  trochanter  minor,  where  it  is 
flattened  behind,  but  strongly  rounded  in  front.  Below  this  point,  it 
becomes  flat  behind,  and,  lower  still,  is  excavated,  while  the  anterior 
surface  is  rounded  throughout.  The  anterior  and  posterior  surfaces  of  the 
bone,  along  the  inner  side,  pass  into  each  other  by  gradual  curvature, 
except  in  the  region  of  the  trochanter  minor.  The  latter  process  is  less 
than  one-third  of  the  way  down  the  shaft,  and  somewhat  stronger  than  in 
the  elephant.     There  is  no  third  trochanter. 

The  cui-ved  front  surface  of  the  femur  is  separated  from  the  flattened 
posterior  face  by  a  rounded  ridge,  extending  along  the  outer  and  posterior 
sides  nearly  the  entire  length  of  the  shaft.  This  ridge  sharply  separates 
the  two  faces,  but  nowhere  rises  conspicuously  above  the  general  sm-face 
of  the  bone,  and  disappears  near  the  proximal  end.  Near  the  distal  end, 
the  surface  is  roughened,  but  is  destitute  of  the  conspicuous  fossa  above  the 
outer  condyle,  seen  in  the  horse  and  the  hippopotamus. 

The  condyles  resemble  those  of  the  elephant,  and,  as  in  that  animal, 
are  so  placed  upon  the  end  of  the  shaft  as  to  permit  the  knee-joint  to  be 
straightened  wdien  standing  at  rest,  and  in  walking.  The  characteristic 
elephantine  gait  must,  therefore,  have  been  assumed  by  the  Dinocerata. 

The  innei-  condyle  is  a  little  greater  than  the  outer  in  transverse 
diameter,  but  much  less  in  antero-posterior  dimensions.  The  two  are 
separated  from  each  other  by  a  deej:)  narrow  sulcus,  but  both  are 
completely  confluent  above  with  the  shallow  and  short  groove  for  the 
patella.  This  groove  is  broadly  rounded  from  side  to  side,  and  less 
distinctly  pulley-shaped,  than  in  the  elephant.  It  is  near  the  middle  of 
the  anterior  surface  of  the  bone,  and  does  not  rise  above  the  general 
sm-face,  except  to  a  very  small  extent  along  its  lateral  margins,  which  are 
acute,  and  sub-equal  in  height 


THE  HIND  LIMBS.  141 

There  is  no  medullary  cavity  in  the  femur,  the  inner  texture  of  the 
shaft  being  merely  somewhat  cancellated,  as  shown  in  the  woodcuts  below. 


Figure  ]37. — Section  of  femur  oi  Dinoceras  mirabile,  Jlarsli  (No.  1206). 
Figure  138. — Section  of  same  bone  (No.  ]210). 

Both  figures  are  one-fourth  natural  size. 

The  main  dimensions  of  the  femur  in  one  specimen  of  Dinoceras  are 
given  below. 

Measiireinents  of  Right  Femur.     (Dinoceras  mirabile,  No.  1206.) 

m. 

Length  of  femur, . . .. .690 

Diameters  of  head, .12.3-126 

Distance  from  summit  of  head  to  tiochanter  minor, . .200 

Height  of  trochanter  minor,    .__ ..._      .015 

Transverse  diameter  through  great  trochanter, .  _ .. . .215 

Least  diameters  of  shaft, ... .... .067-.093 

Transverse  diameter  of  distal  end,   _    . _.    .170 

Greatest  antero-posterior  diameter  of  distal  end, 160 

Least  antero-posterior  diameter  of  distal  end, . .     .100 

Transverse  diameter  of  inner  condyle, .065 

Transverse  diameter  of  outer  condyle, ^ .... ..     .070 


The  Tibia.     (Plate  XLV.) 

The  tibia  in  the  JDinocerata  is  much  shorter  than  tlie  femur,  as  in  the 
elephant  and  the  mastodon,  and  considerably  resembles  the  same  bone  in 
these  animals.  It  differs  noticeably  in  the  greater  prominence  of  the 
tuberosity  for  the  attachment  of  the  patellar  ligament. 

The  proximal  articular  surfaces  for  the  condyles  of  the  femur  are 
confluent,  or  very  nearly  so,  being  separated  by  only  a  low,  smooth  and 
rounded  ridge,  as  seen  in  Plate  XLV,  figure  3  a.  The  inner  face  is 
larger    in    antero-posterior    diameter    than    the    outer,    and    is    concave 


142  DINOCERATA. 

throughout  in  both  directions,  except  for  a  very  small  area  near  its  posterior 
margin.  The  outer  face  is  shoi'ter,  but  much  broader  than  the  inner,  and 
posteriorly  is  much  more  convex,  and  thus  adapted,  in  extreme  flexion  of 
the  leg,  to  a  concave  face  on  the  outer  condyle  of  the  femur.  These  faces 
may  indicate  the  presence  of  a  flabella. 

Below  the  oixter  and  posterior  part  of  this  articular  surface,  is  a  small 
flattened  facet,  looking  nearly  downward,  and  somewhat  outward  and 
backward,  for  articulation  with  the  fibula. 

The  upper  end  of  the  shaft  presents  in  front  a  deep  rounded 
excavation,  bounded  at  the  sides  and  below  by  a  roughened  curved  ridge 
for  muscular  attachment.  The  shaft  is  conti-acted  in  the  middle,  but 
expands  below,  and  has  its  distal  end  nearly  covered  by  the  broad  surface 
for  articulation  with  the  astragalus. 

This  articular  face  is  confluent  along  its  outer  margin  with  a  small 
oblique  face  for  the  distal  end  of  the  fibula.  It  is  concave  antero- 
posteriorly,  but,  in  transverse  section  across  the  middle,  is  at  first  slightly 
convex  on  the  internal  malleolus,  then  concave,  and  again  moderately 
convex  to  the  margin  of  the  fibular  articulation.  This  face  is  represented 
in  Plate  XLV,  figure  1  a. 

The  tibia  is  nearly,  or  quite,  solid,  as  shown  in  figure  5  of  the 
same  Plate. 

Measurements  of  Tibia.      {Dinoceras  mirabile,  No.  1208.) 

m. 

Total  length  of  tibia,  .-_ .390 

Greatest  diameter,  proximal  end, .140 

Antero-posterior  diameter,  below  patella, . .096 

Antero-posterior  diameter  of  inner  proximal  articular  surface, -    .080 

Transverse  diameter  of  inner  proximal  articular  surface, .  _ . 062 

Antero-fiosterior  diameter  of  outer  proximal  articular  surface, —     .070 

Transverse  diameter  of  outer  proximal  articular  surface,   .075 

Greatest  diaiiieter  of  fibidar  articular  surface,   . .033 

Least  diameter  of  fibular  articul.ar  surface, .027 

Least  diameters  of  shaft, . .  — .052-.057 

Greatest  diameter,  distal  end, ... ._.... .107 

Antero-posterior  diametei',  distal  end, .093 

Greatest  diameter  of  astragalar  surface  (approximate), .095 

Antero-posterior  diameters  of  astragalar  surface, ...-. .067-080 

Antero-posterior  diameter  of  distal  fibular  surface,  _  _    .  _ .035 

Least  diameter  of  distal  fibular  surface, - 015 


THE   HIND   LIMBS.  143 

The  Fibula.     (Plate  XLVI,  figures  1-4.) 

The  fibula  is  slender,  and  entire,  with  articular  faces  well  marked  at 
each  extremity.  The  proximal  end  is  somewhat  expanded,  and  has  the 
articular  face  for  union  with  the  tibia  oblique,  and  sub-oval  in  outline. 
The  shaft  is  somewhat  twisted,  and  sub-triangular  in  transverse  section. 
The  distal  end  of  the  fibula  is  larger  than  that  above,  and  quite  rugose. 
The  articulation  for  union  with  the  astragalus  is  large,  and  placed 
obliquely,  as  shown  in  Plate  XLVI,  figure  4. 

In  some  specimens  of  the  Dinocerata,  and  probably  in  all,  the  fibula 
met  the  calcaneum,  as  in  Corypliodon,  and  the  Artiodfictyls. 

Measurements  of  the  fibula  in  two  individuals  of  JDinoceras  are  as 
follows : 

Measurements  of  Fibula.     [Dinoceras  niirabile,  No.  1208.) 

m. 

Length  of  fibula  (approximate), , .350 

Diameters  of  proximal  end, .040-045 

Diameters  of  proximal  articular  surface, . .028-033 

Measurements  of  Fibula.      {Dinoceras  mirabile,  No.  1210.) 

m. 

Diameters  of  shaft, .028-020 

Diameters  of  distal  end, .040-070 

Diam.eters  of  distal  articular  surface  (approximate), .050-045 


The  Patella.     (Plate  XLVI,  figures  5-8.) 

The  patella  in  the  Dinocerata  is  a  large  bone,  and  resembles,  in  its 
general  features,  that  of  the  elephant,  Its  external  surface  is  quite 
rugose.  The  articular  surface  for  union  with  the  condyles  of  the  femur 
is  sub-oval  in  outline,  concaA^e  from  above  downward,  and  transversely 
convex  in  consequence  of  the  usual  median  swelling.  The  general 
characteristics  are  well  represented  in  Plate  XLVI,  and  its  position  in  the 
skeleton  is  shown  in  the  restorations  at  the  end  of  the  volume,  Plates  LV 
and  LVI. 


CHAPTER     XII. 


THE    HIND    LIMBS.       (Continued.) 
(Plates  XLVII-LVI.) 

The  hind  feet  in  the  JDinocerata  were  considerably  smaller  than  those 
in  front.  Their  component  parts  are  short  and  robust,  forming  together  a 
strong  support  for  the  massive  hind  limbs.  There  were  five  digits,  as  in 
the  Proboscidians,  and  the  axis  of  the  foot  was  through  the  third,  or 
middle,  digit. 

The  general  appearance  of  the  hind  foot  in  Dinoceras  mirahile  is 
represented  in  Plate  LIV,  figure  2.  The  fore  foot,  or  manus,  is 
seen  in  figure  1  of  the  same  Plate,  and  both  feet  are  shown  in  different 
positions  in  the  restorations.  Plates  LV  and  LVI. 

The  Tarsal  Bones. 

(Plates  XLYII-L,  Plate  LIV,  figure  2  ;  and  woodcuts 
139-146,  below.) 

There  are  seven  well  developed  tarsal  bones  in  the  Binocerata,  and 
their  relative  position  in  the  hind  foot  is  seen  in  Plate  LIV.  These  bones 
are  described  in  detail  below.  An  eighth  tarsal  bone,  the  tibiale,  appears 
to  have  been  present. 

19  145 


146  DINOCERATA. 

The  Astragalus. 
(Plate  XLVII,  Plate  LIV,  figure  2,  a;  and  woodcuts  139-142,  below.) 

The  astragalus  in  the  Binocerata  considerably  resembles  that  of  the 
elephant,  the  bone  being,  as  in  that  animal,  very  short,  along-  the  axis  of 
the  leg  and  foot.  The  articular  faces  are,  moreovei',  but  little  curved, 
indicating  comparatively  slight  freedom  of  motion  in  the  ankle  joint. 

The  superior,  or  proximal,  face  of  the  bone,  articulating  with  the  tibia, 
is  shown  in  Plate  XLVII,  figin-e  1.  This  surface  is  sub-quadrate  in 
general  outline,  with  rounded  angles,  but  is  jjrolonged  posteriorly  on  the 
inner,  or  tibial,  side  into  a  large  convex  lobe. 

The  surface  of  the  tibial  articulation  is  moderately  convex  from 
before  backward,  and,  in  front,  nearly  flat  from  side  to  side,  but, 
posteriorly,  it  becomes  somewhat  excavated,  this  being  the  only  indication 
of  the  conspicuous  groove  common  in  Ungulates.  The  tibial  articular 
surface  is  confluent,  along  the  posterior  part  of  its  outer  margin,  with  a 
somewhat  convex,  rounded  face  for  the  fibula,  as  shown  in  figure  4. 

The  inner  surface  of  the  bone  (figure  2),  or  that  which  is  presented 
upon  the  tibial  side  of  the  foot,  is  excavated  by  a  large,  rounded 
depression,  encroaching  above  upon  the  margin  of  the  tibial  articular  face. 

Below  this  depression,  the  bone  is  expanded,  and  presents  a  rounded 
and  convex  articular  surface,  in  close  relation  with  the  adjoining,  and 
nearly  or  quite  confluent,  face  for  articulation  with  the  navicular,  as  shown 
in  figure  140,  f  below.  This  convex  facet  apparently  supported  a  separate 
bone,  as  in  the  existing  Hyrax  (figure  155,  Chapter  XIV).  This  bone, 
as  Baur  has  suggested,  probably  represents  the  tibiale,  or  inner  tarsal  of 
the  jjroximal  row.  The  same  bone  exists  also  in  Hystrix,  and  many  other 
Rodents,  and  is  regarded  by  Flower  as  a  sesamoid. 

Tlie  inferior  surface  of  the  astragahis  (Plate  XLVII,  figi;re  3) 
articulated  with  three  bones ;  below,  with  the  upper  faces  of  the 
calcaneum,  and,  in  front,  with  the  navicular  and  the  cuboid.  All  these 
articular  faces  may  be  confluent,  as  in  the  specimen  figm-ed  on  the  Plate, 
and  the  mode  of  union  with  the  calcaneum  is  subject  to  considerable 
variation. 


THE  HIND  FEET.  147 

In  the  specimen  there  figured,  the  face  for  the  calcaneum  may  be 
briefly  described  as  in  the  form  of  a  horse-shoe  with  the  lateral  branches 
so  broad  as  to  leave  only  a  narrow  interval  between  them. 

The  lateral  portions,  or  branches,  present  two  oval,  concave  faces, 
and  they  are  united  behind  by  a  broad  band,  running'  around  the 
posterior  end  of  a  deep,  narrow  groove,  dividing  the  anterior  parts  of  the 
articulation,  and  leading  backward  to  a  foramen  through  the  bone.  In 
the  speciman  figured,  this  foramen  is  small  and  oblique,  and  no  opening 
is  seen  through  the  bone.  Along  the  outer,  or  fibular,  margin  of  the 
bone,  the  articular  face  is  confluent  for  a  short  distance  with  that  for  the 
fibula  on  the  side  of  the  astragalus.  Near  the  center  of  the  inferior  surface, 
the  inner  ramus  of  the  calcaneal  articular  facet  is  confluent  at  the  end  with 
tlie  face  for  the  cuboid. 

Another,  and  more  common,  form  of  articulation  with  the  calcaneum 
is  shown  in  figure  140,  below,  where  the  lower  surface  of  the  astragalus 
presents  two  distinct  faces  for  the  calcaneum.  The  outer  of  these  is  broad 
and  rounded,  nearly  flat  transversely,  concave  from  before  backward,  and 
separated  by  a  deep  groove  from  the  inner,  more  elongated  surface.  This 
groove  leads  backward  into  a  large  foramen,  passing  through  the  postei'ior 
part  of  the  bone.  The  inner  portion  of  the  calcaneal  face  is  longer  than 
the  outer,  and  more  concave  from  before  backward,  From  side  to  side,  it 
is  nearly  flat,  and,  in  front,  it  is  more  or  less  confluent  with  the  face  for  the 
cuboid,  and  often  also  with  that  for  the  navicular.  In  a  few  specimens, 
the  usual  foramen  near  the  hinder  border  of  the  bone  is  represented  by  a 
notch  only,  as  in  figures  141  and  142,  below. 

The  anterior  part  of  the  under  surface  of  the  astragalus  presents  two 
flattened,  moderately  convex,  and  very  unequal,  articular  faces.  The 
larger  one  of  these  is  for  articulation  with  the  navicular,  and  the  smaller, 
for  the  cuboid  bone. 

The  presence  of  a  face  for  the  cuboid  is  in  sti'ong  contrast  with  the 
structure  of  the  foot  of  the  elephant,  in  which  the  cuboid  is  supported  by 
the  calcaneum,  and  the  navicular  which  covers  the  Avhole  anterior  face  of 
the  astragalus,  not  allowing  the  cuboid  to  come  in  contact  with  that  bone. 
In  the  Dinocerata,  this  specialization  does  not  occur. 


148  DINOCERATA. 

The  face  for  the  navicular  is  fully  twice  as  large  as  that  for  the 
cuboid.  It  is  somewhat  convex  from  side  to  side,  but  is  nearly  flat 
from  before  backward,  and  is  bonnded  along  its  outer,  or  fibular,  and 
posterior  side  by  a  low  rounded  ridge,  indicating  the  limit  of  the  cuboid 
face.  This  facet  is  more  or  less  triangular  in  outline,  the  apex  pointing 
backward  and  inward.     It  is  only  moderately  convex. 

The  relation  of  the  navicular  face  to  the  articulation  for  the  tibiale 
bone  is  well  shown  in  woodcuts  140  and  142,  below. 

The  outer,  or  fibular,  side  of  the  astragalus  (Plate  XL VI I,  figure  4) 
presents  a  convex  articulation  for  the  fibula.  This  face  is  confluent  above, 
with  the  tibial  surface,  and  usually,  also,  in  a  much  less  degree,  with  the 
outer  face  for  the  calcaneum.  In  some  specimens,  however  (numbers 
1248,  1528,  1531),  these  faces  are  quite  separated. 

In  an  anterior  view  of  the  astragalus  (figure  5),  the  exterior,  or 
dermal,  surface  is  seen  to  be  very  short,  proportionally  shorter  than  in  the 
elephant,  but  varying  within  such  limits  that  the  longest  in  the  JDinocerata 
may  nearly  or  quite  equal  in  length  the  shortest  in  the  elephant. 

Posteriorly,  the  astragalus  extends  backward  much  farther  on  the 
inner,  or  tibial,  side  than  on  the  outer  side,  and  is  tuberculated.  This 
surface  of  the  bone  is,  in  some  specimens,  deeply  notched  near  the  middle, 
as  in  figures  141  and  142,  below,  but  more  commonly  the  notch  is 
converted  into  a  foramen  by  a  bridge  of  bone,  as  in  Plate  XLVII,  figure 
6,  and  figures  139  and  140,  below.  The  tibial  articular  surface  is  not 
usually  confluent  with  the  calcaneal  surface,  as  is  sometimes  the  case  in 
the  elephant.  A  near  approach  to  confluence  is  seen  in  one  specimen, 
number  1209. 

The  astragalus  in  Gorypliodon  is  very  similar  in  form  to  that  in  the 
Dinocemta,  but  is  shorter.  It  has  essentially  the  same  articular  faces,  and 
the  facet  for  the  tibiale  is  equally  well  marked.  The  hind  foot  of 
Gorypliodon  is  shown  in  figure  151,  in  Chapter  XIV.  Its  general 
resemblance  to  the  corresponding  foot  in  Dmoceras  is  striking,  and  the 
structure  of  the  two  is  essentially  the  same.  The  resemblance  between 
the  fore  foot  of  Dinoceras  and  that  of  Coryphodon  is  equally  marked. 


THE   HIND   FEET. 


149 


The    astragalus    in    one    individual    of    Dinoceras,    and    in    one    of 
Tinoceras,  is  represented  in  the  woodcuts  below. 

Fig.  139.  Fro.  UO. 


FiGUHB  139 — Left  astragalus  of  Dinoceras  laticeps,  ^larsh  {No,  IISI);  top  view  ;   slmwing  foramen. 
Figure  140. — Tlie  same  boue;  bottom  view. 

h.  face  for  fibula;  c.  and  c'.  faces  for  calcaneum;  rM.  face  for  cuboid;  n.  face  for  navicular;  t.  fnce  for 

tibia,  i'.  face  for  tibiale. 


FrenEE  141. — Left  astragalus  of  Tinoceras  ingens,  Marsh  (No.  1209);  top  view. 
FiUUKE  142. — Tlie  same  bone ;  bottom  view. 

c.  and  c'.  faces  for  calcaneum ;   ch.  face  for  cuboid ;  /.  face  for  fibula ;  n.  face  for  navicular,  t,  face  for  til:)ia. 
All  the  figures  are  one-half  natural  size. 


150  DINOCERATA. 

Measurements  of  the  astragalus  in  four  individuals  of  the  Dinocerata 
are  as  follows : 

Measurements  of  the  Left  Astragalus.     (Dinoceras  mirabile,  No.  1210.) 

m. 

Greatest  antero-posterior  diameter  of  astragalus, .112 

Greatest  transverse  diameter, . .121 

Greatest  vertical  diameter, . ^ .070 

Greatest  diameter  of  articular  face  for  tibia, .110 

Antero  posterior  diameters  of  articular  face  for  tibia,. .072-.066-.092 

Transverse  diameters  of  articular  face  for  tibia, . .07t3-.071-.085 

Antero-posterior  diameter  of  articular  face  for  fibula, .044 

Vertical  diameter  of  articular  face  for  fibula,  .    ._- .._.     .036 

Antero-posterior  diameter  of  articular  face  for  calcaneum, — .054 

Transverse  diameter  of  articular  face  for  calcaneum, _. .080 

Transverse  diameter  of  articular  face  for  calcaneum,  outer  lobe, .033 

Transverse  diameter  of  articular  face  for  calcaneum,  inner  lobe, _     .040 

Diameter  of  band  connecting  lobes, .-    .018 

Antero-posterior  diameter  of  united  faces  for  navicular  and  cuboid, — .056 

Transverse  diameter  of  united  faces  for  navicular  and  cuboid, .107 

Diameters  of  face  for  navicular, .. .066-.082 

Diameters  of  face  for  cuboid, .035-062 

Minimum  length  of  neck, .014 


Measurements  of  Left  Astragalus.     {Dinoceras  laticeps.,  No.  1197.) 

m. 

Greatest  antero-posterior  diameter  of  astragalus, .128 

Greatest  transverse  diameter, ... .128 

Greatest  vertical  diameter, 080 

Greatest  diameter  of  articular  face  for  tibia, 127 

Antero-posterior  diameters  of  articular  face  for  tibia,.. .(iS9-.080-.105 

Transverse  diameters  of  articular  face  for  tibia, .090-.085-.09I 

Antero-posterior  diameter  of  articular  face  for  fibula, 065 

Vertical  diameter  of  articular  face  for  fibula, ..     .031 

Antero-posterior  diameter  of  outer  articular  face  for  calcaneum, .053 

Transverse  diameter  of  outer  articular  face  for  calcaneum,.  _  ...    .048 

Antero-posterior  diameter  of  inner  articular  face  for  calcaneum, .     .061 

Transverse  diameter  of  inner  articular  face  for  calcaneum, .... .035 

Distance  between  inner  and  outer  faces  for  calcaneum, .....     .009 

Antero-posterior  diameter  of  united  faces  for  navicular  and  cuboid, .     .072 

Transverse  diameter  of  united  faces  for  navicular  and  cuboid, 113 

Diameters  of  face  for  navicular, .064-091 

Diameters  of  face  for  cuboid, .031-071 

Minimum  length  of  neck, ...... 016 


THE   HIND    FEET.  151 

Measicrements  of  Left  Astragalus.     (T'moceras  ingens.  No.  1209.) 

m. 

Greatest  antero-posterior  diameter  of  astragalus, .122 

Greatest  trausverse  diameter, .147 

Greatest  vertical  diameter, ,.     .083 

Greatest  diameter  of  articular  face  for  tibia, ..  _     .125 

Antero-posterior  diameters  of  articular  face  for  tibia _ 09 1-.082-.  1  04 

Transverse  diameters  of  articular  face  for  tibia, .094-,096-.095 

Antero-posterior  diameter  of  articular  face  for  fibula, .000 

Vertical  diameter  of  articular  f :ice  for  fibula, .039 

Antero-posterior  diameter  of  outer  articular  face  for  calcaneum, .050 

Transverse  diameter  of  outer  articular  face  for  calcaneum, .... .      .050 

Antero-posterior  diameter  of  inner  articular  face  for  calcaneum, .058 

Transverse  diameters  of  inner  articular  face  for  calcaneum, .033-050 

Distance  between  inner  and  outer  faces  for  calcaneum, .013 

Antero-posterior  diameter  of  united  faces  for  navicular  and  cuboid, .068 

Transverse  dinmeter  of  united  faces  for  navicular  and  cuboid, .130 

Diameters  of  face  for  navicular, .068-.  105 

Diameters  of  face  for  cuboid, 042-.077 

Minimum  length  of  neck,,  _ .019 

Measurements  of  Right  Astragalus.     [Dinoceras  mirabile,  No.  1528.) 

m. 
Greatest  antero-posterior  diameter  of  astragalus, .100 

Greatest  transverse  diameter, 108 

Greatest  vertical  diameter, 063 

Greatest  diameter  of  articular  face  for  tibia, __      .loo 

Antero-posterior  diameters  of  aiticular  face  for  tibia, ....   ,070-.000-.093 

Transverse  diameters  of  articular  face  for  tibia, .067-.067-.070 

Antero-posterior  diameter  of  articular  face  for  fibula, .040 

Vertical  diameter  of  articular  face  for  fibula, .    . .030 

Antero-posterior  diameter  of  outer  articular  face  for  calcaneum,  .    .035 

Transverse  diameter  of  outer  articular  face  for  calcaneum, .039 

Antero-posterior  diameter  of  inner  articular  face  for  calcaneum, .040 

Transverse  diameter  of  inner  articular  face  for  calcaneum, .040 

Antero-posterior  diameter  of  united  articular  faces  for  navicular  and  cuboid, .053 

Transverse  diameter  of  united  articular  faces  for  navicular  and  cuboid, .093 

Diameters  of  face  for  navicular, .076-.053 

Diameters  of  face  for  cuboid, . .026-055 ' 

Minimum  length  of  neck, . .015 

The    Calcaneum. 

(Plate  XLVIII,  Plate  LIV,  figure  2,  c;  and 

woodcuts  143-144,  below.) 

The  calcaneum  in  the  Dinocerata  is  short,  and   comparatively  more 

robust,  than  in  the  elephant.     As  in  that  animal,  it  is  strongly  tuberculated 


152 


DINOCERATA. 


below,  where,  during  life,  it  doubtless  supported  a  thick  pad,  resting  on 
the  ground. 

The  calcaneum  articulated  mainly  with  two  bones,  the  astragalus  and 
the  cuboid.  Some  specimens,  and  j^erliaps  all,  present  a  small  face  where 
the  fibula  touched  this  bone. 

The  articulation  with  the  astragalus  is,  in  most  specimens,  divided  into 
two  distinct  facets  (figures  144,  a  and  a')  by  a  deep  groove.  In  some 
cases,  however,  these  facets  are  coalescent  posteriorly,  as  in  Plate  XLVIII, 
figm-es  1  and  5,  and  in  figure  143,  corresponding  with  a  similar  coalescence 
of  faces  on  the  astragalus. 

The  face  for  the  cuboid  is  small,  and  irregularly  rounded,  or  oval,  as 
seen  in  Plate  XLVIII,  figure  1,  and  is  usually  more  or  less  confluent  with 
the  inner  face  for  the  astragalus,  but  is  well  separated  from  the  outer  face 
for  that  hone. 

The  great  tuberosity  for  the  attachment  of  the  tendo  Achillis  is 
very  short,  proportionally  shoi'ter  than  in  the  elejjhant. 


Figure  14'-. — Calcaneum  of  Dinoceras  miriMle,  Marsh  (^fo.  1210);  top  view. 
Figure  144. — GalcaDeum  of  Dinoceras  mirabile,  (No.  1208);  top  view. 
a.  and  a',  faces  for  astragalus. 

Both  fisrures  arc  oue-lialf  uatural  sizo 


Two  specimens  of  the  calcaneum  in  different  individuals  of  Dinoceras 
are  represented  in  tlie  woodcuts  above. 

Measurements  of  three  specimens  of  the  calcaneum  in  the  Dinocerata 
are  as  follows : 


THE    HIND   FEET.  153 

Measurements  of  Left  Calcaneum.     (Dinoceras  mirabile,  No.  1210.) 

m. 

Length  of  calcaneum,  from  great  tuberosity  to  face  for  cuboid, .096 

Transverse  diameter, ._- .-.    _..--  .090 

Vertical  diameter, .070 

Antero-posterior  diameter  of  inner  lobe  of  articulation  for  astragalus, . .050 

Transverse  diameter  of  inner  lobe  of  articulation  for  astragalus, .043 

Antero-posterior  diameter  of  outer  lobe  of  articulation  for  astragahis, .043 

Transverse  diameter  of  outer  lobe  of  articulation  for  astragalus  (ap]iroximate), .039 

Measurements  of  Right  Calcaneum.     (Dinoceras  mirabile, 'So.  1225.) 

m. 

Ijcngth  of  calcaneum,  from  great  tuberosity  to  face  for  cuboid, .107 

Transverse  diameter  (approximate), .... .086 

V  ertical  diameter, .074 

Antero-posterior  diameter  of  inner  face  for  astragalus, .053 

Transverse  diameter  of  inner  face  for  astragalus, .087 

Antero-posterior  diameter  of  outer  face  for  astragalus, .045 

Transverse  diameter  of  outer  face  for  astragalus  (approximate), .037 

Distance  between  inner  and  outer  faces  for  astragalus, .010 

Measurements  of  Left  Calcaneum.     (Dinoceras  inirabile,'So.  1208.) 

m. 

Length  of  calcaneum,  from  great  tuberosity  to  face  for  cuboid, 093 

Transverse  diameter, .086 

Vertical  diameter, . .074 

Antero-posterior  diameter  of  inner  face  for  astragalus, , 044 

Transverse  diameter  of  inner  face  for  astragalus, ._ .042 

Antero-posterior  diameter  of  outer  face  for  astragalus, .. .050 

Transverse  diameter  of  outer  face  for  astragalus, . .032 

Distance  between  faces  for  astragalus, .070 

Transverse  diameter  of  face  for  cuboid, .035 

Vertical  diameter  of  face  for  cuboid, .019 


The  Cuboid. 

(Plate  XLIX,  figures  1-6,  Plate  LIV,  figure  2,  cb;  and 

woodcuts  145-146,  below.) 

The  cuboid  in  the  Dinocerata  corresponds  in  general  with  that-  of  the 

elephant,   and  presents  similar  articular  faces,   though   not  to   the   same 

bones.     It  is  also  more  elongated  in  the  line  of  the  axis  of  the  foot,  thus 

appearing  less  flattened  than  in  the  Proboscidea.      In  general  shape,  the 

bone  is  triangular,  the  longest  side  being  nearly  straight,  and  lying  along 

the  inner,  or  side  for  the  navicular,  while  the  shortest  side  is  somewhat 

curved,  and  is  presented  to  the  exterior,  or  dorsal,  surface  of  the  foot. 


154  DINOCERATA. 

This  surface  (Plate  XLIX,  figure  1)  is  moderately  roughened, 
especially  at  the  edges,  for  attachments  of  ligaments.  The  outer,  or 
fibular,  side,  shown  best  in  figure  4,  is  short  along  the  line  of  the  foot,  being 
encroached  upon  by  the  articular  face  for  the  calcaneum  on  the  proximal 
end,  and  one  for  the  fifth  metatai'sal  on  the  distal  end. 

The  plantar  aspect  of  the  bone  (figure  3)  presents  a  single,  or  bifid, 
tubercle,  and,  on  the  inuer  face  (figure  2),  is  an  elongate  articular  surface 
for  union  with  the  navicular.  This  surface  is  confluent  with  the  face  for 
articulation  witli  the  astragalus,  and  thus  serves  to  distinguish  the  proximal 
from  the  distal  end  of  the  bone,  which  often  closely  resemble  each  other. 

The  proximal  surface  (figure  5)  is  covered  by  two  articular  facets. 
The  inner  one,  large  and  sub-triangular,  concave  in  both  directions,  and 
nearly  perpendicular  to  the  axis  of  the  bone,  moved,  during  life,  upon  the 
outer  distal  face  of  the  astragalus.  This  face  is,  in  the  specimen  figured 
on  the  Plate,  widely  confluent  with  a  smaller  oval  face  for  the  calcaneum. 
In  figure  146,  below,  the  face  for  the  calcaneum  (c)  is  much  less  widely 
confluent  with  that  for  the  astragalus,  being  nearly  separated  from  it. 
In  both  specimens,  the  calcaneal  face  is  slightly  convex  transversely,  and 
somewhat  inclined  to  the  axis  of  the  bone. 


PieuRE  145. — Right  culioid  of  Dimceras  miraUle,  Marsh  (No.  1528);  siile  view 
Figure  146. — The  same  bone  ;  pro.ximal  end. 

a.  face  for  astragalus;  c.  face  for  calcaneum ;  mt  IV.  face  for  fourth  metacarpal ;  n.  face  for  navicular. 
Both  figures  are  one-half  natural  size. 

The  cuboid  bone  in  one  individual  of  Dinoceras  is  represented  in  the 
two  cuts  above. 

The  distal  face  (Plate  XLIX,  figure  6)  also  presents  two  articular 
surfaces,  for  the,  support  of  tlie  fourth  and  fifth  metatarsal  bones.     The 


THE   HIND   FEET.       •  155 

face  for  the  fourth  metatarsal  is  much  the  larger.     It  is  narrow,  or  pointed, 

below,   and  moderately  concave,  or,  in  the  lower  part,  slightly  convex, 

from  above  downward,  and  is  at  right  angles  with  the  axis  of  the  bone. 

The  smaller  outer  face,  supporting  the  fifth  metatarsal,  is  turned  somewhat 

outward,  and  is  slightly  convex  in  both  directions. 

The  principal  dimensions  of  the  two  cuboid  bones  above  described 

are  as  follows : 

Measurements  of  Left  Cuboid.     {Dinoceras  mirabile.  No.  1208.) 

m. 

Length  of  cuboid,  along  axis  of  foot, .035 

Transverse  diameter,   .054 

Antero-posterior  diameter, _ ._  .060 

Antero-posterior  diameter  of  face  for  astragalus, . .    .055 

Transverse  diameter  of  face  for  astragalus, .034 

Antero-posterior  diameter  of  face  for  cuboid, .035 

Transverse  diameter  of  face  for  cuboid, .020 

Antero-posterior  diameter  of  face  for  fourth  metatarsal, .049 

Transverse  diameter  of  face  for  fourth  metatarsal,  . _   .032 

Antero-posterior  diameter  of  face  for  fifth  metatarsal, .035 

Transverse  diameter  of  face  for  fifth  metatarsal, _. _.  .022 

3Ieasurements  of  Right  Cuboid.     [Dinoceras  mirabile,  No.  1528.) 

m. 

Length  of  cuboid,  along  axis  of  foot, .037 

Transverse  diameter, .    . ......  .066 

Antero-posteri6r  diameter,  _.__  .... . .065 

Antero-posterior  diameter  of  face  for  astragalus,   _.    _ 058 

Transverse  diameter  of  face  for  astragalus, . .036 

Antero-posterior  diameter  of  face  for  cuboid, .. .032 

Transverse  diameter  of  face  for  cuboid, .026 

Antero-posterior  diameter  of  face  for  fourth  metatarsal, .049 

Transverse  diameter  of  face  for  fourth  metatarsal, .035 

Antero-posterior  diameter  of  face  for  fifth  metatarsal, .039 

Transverse  diameter  of  face  for  fifth  metatarsal, .032 


The  Navicular. 
(Plate  XLIX,  figures  7-12,  and  Plate  LIV,  figure  2,  n.) 
The  navicular  is  a  short  bone  in  the  Dinocerata,  strongly  flattened 
vertically,  much  as  in  the  elephant.  It  is  supported  b}^  the  astragalus, 
and  does  not  usually,  as  in  that  animal,  touch  the  calcaneum.  It  supports 
only  the  three  cuneiform  bones  in  front,  but  presents  a  narrow,  lateral, 
articular  face  to  the  cuboid. 


156  DINOCERATA. 

The  surface  of  the  navicular  exposed  upon  the  dorsal  aspect  of  the 
foot  (Plate  XLIX,  figure  7)  is  short  vertically,  more  or  less  rounded 
from  side  to  side,  and  varies  much  in  the  degree  of  smoothness,  or 
tuberculation,  in  different  specimens. 

The  under,  or  plantar,  surface,  shown  in  figure  9,  projects  into  a 
large  rounded  tubercle,  and  is  of  considerably  greater  extent  along-  the  axis 
of  the  foot  than  above. 

The  outer  surface  (figure  10),  presented  to  the  cuboid,  is  more  or  less 
covered  by  an  articular  face,  extending  along  the  proximal  margin  of  the 
bone,  confluent  with  the  astragalar  face,  and,  in  life,  moving-  upon  a 
corresponding-  face  upon  the  inner  side  of  the  cuboid. 

The  proximal  surface  of  the  bone  (figure  11)  is  mostly  occupied  by  a 
large  articular  surface,  for  union  with  the  astragalus.  This  surface  is 
somewhat  saddle-shaped,  being-  distinctly  concave  transversely,  but 
somewhat  convex  from  above  downward.  Below  the  articular  face,  the 
bone  usually  extends  into  a  sti-ong-  plantar  tubercle,  which  may,  however, 
(number  1218)  be  much  less  developed  than  in  the  specimen  figm-ed. 

None  of  the  specimens  present  any  indication,  on  the  proximal  face, 
of  a  surface  for  articulation  with  the  calcaneum,  such  as  is  found  on  the 
corresponding  bone  of  the  elephant. 

The  distal  surface  of  the  navicular  (figure  12)  presents  tliree  articular 
faces,  one  for  each  of  the  cuneiform  bones.  These  faces  are  confluent 
with  each  other,  and  the  inner  one,  for  the  entocuneiform,  may  be  small, 
and  indistinct.  Usually,  it  is  of  considerable  size,  and  elongated  fi-om 
above  downward.  It  is  oval  in  shape,  moderately  convex  in  both 
directions,  and  oblique  to  the  axis  of  the  bone,  looking-  somewhat  outward. 
The  median  of  the  three  faces  is  sub-quadrate  in  outline,  a  little  broader 
above  than  below,  and  confluent,  on  each  side,  with  the  adjacent  faces. 
This  face  is  slightly  concave  from  side  to  side,  and  from  above  downward, 
nearly  flat. 

The  face  for  the  ectocuneiform  is  sub-quadrate,  tapering  below,  concave 
in  both  directions,  or  nearly  flat  from  above  downward. 


THE   HIND   FEET.  157 

These  faces  may  all  be  considerably  shorter  and  broader  than  in  the 
specimen  figured,  and  the  face  for  the  entocuneiform  may  be  very  greatly 
reduced. 

The  following  measurements  of  three  specimens  of  the  navicular  in 
Dinoceras  show  the  more  important  dimensions  of  this  bone  : 

Measurements  of  Left  Navkidar.     [Dinoceras  mirabile,'i^o.  1247.) 

m. 

Transverse  diameter  of  navicular, ' .085 

Antero-posterior  diameters  (axial), .. .015-.029 

Transverse  diameter  of  face  for  astragalus, .080 

Vertical  diameter  of  face  for  astragalus, .060 

Transverse  diameter  of  face  for  entocuneiform, _.      .020 

Vertical  diameter  of  face  for  entocuneiform, .050 

Transverse  diameter  of  face  for  mesocuneif orm, . .025 

Vertical  diameter  of  face  for  mesocuneif  orm, ... .045 

Transverse  diameter  of  face  for  ectocuneiform, . .035 

Vertical  diameter  of  face  for  ectocuneiform  (approximate),  ., .055 

Measurements  of  Left  Navicular.     {Dinoceras  niirabile,  No.  1208.) 

m. 

Transverse  diameter  of  navicular, .. .. .06  7 

Antero-posterior  diameters, .015-.025 

Vertical  diameter, .069 

Transverse  diameter  of  face  for  astragalus, .058 

Vertical  diameter  of  face  for  astragalus, .051 

Transverse  diameter  of  face  for  entocuneiform, 022 

Vertical  diameter  of  face  for  entocuneiform, ..- 033 

Transverse  diameter  of  face  for  mesocuneif  orm, .. .02f) 

Vertical  diameter  of  face  for  mesocuneif  orm, ._     .043 

ransverse  diameter  of  face  for  ectocuneiform,  _ __ __      .032 

Vertical  diameter  of  face  for  ectocuneiform, .040 

Measurements  of  Left  Navicular.     {Dinoceras  mirabile,  No.  1218.) 

ra. 

Transverse  diameter  of  navicular, '. j .082 

Antero-posterior  diameters, __  .015-022 

Vertical  diameter, ^ . -065 

Transverse  diameter  of  face  for  astragalus, .065 

Vertical  diameter  of  face  for  astragalus, .'   .050 

Transverse  diameter  of  face  for  entocuneiform  (approximate), _    .012 

Vertical  diameter  of  face  for  entocuneiform, .028 

Transverse  diameter  of  face  for  mesocuneiform, .029 

Vertical  diameter  of  face  for  mesocuneiform  (approximate), 045 

Transverse  diameter  of  face  for  ectocuneiform, _. .037 

Vertical  diameter  of  face  for  ectocuneiform, .052 


158  DINOCERATA. 

The  Entocuneiform. 
(Plate  L,  figures  1-6,  and  Plate  LIV,  figure  2,  en.) 

The  entocuneiform  in  the  Dinocerata  bears  but  slight  resemblance  to 
the  corresponding  bone  in  the  elephant.  It  is  much  less  elongated  in  the 
line  of  the  axis  of  the  foot,  and  even  less  so  than  appears  in  the  general 
view  of  the  hind  foot  on  Plate  LIV,  since  the  elongation  apparent  in 
that  figure  is,  to  a  great  extent,  in  front  of  the  articular  surfaces.  These 
surfaces  are,  at  their  nearest  points,  scarcely  more  widely  separated  in  the 
direction  of  the  axis  of  the  foot,  than  are  those  of  the  other  cuneiform 
bones. 

The  dermal  surface  of  the  bone  (Plate  L,  figure  1)  is  rotigh  and 
tuberculated,  often  much  more  so  than  represented  in  the  figure.  It  is 
also  usually  more  elongated  in  the  axial  direction,  in  front  of  the  articular 
surfaces. 

The  opposite  surface  of  the  bone  (figure  3)  is  flattened,  and 
moderately  roughened,  and  presents  a  small  area  only  for  articulation 
with  the  mesocuneiform.  This  articular  face  is  conflxient  with  the  face 
for  the  navicular,  and  lies  along  the  anterior  part  of  its  margin. 

The  proximal  articular  face  (figure  5)  is  of  a  semi-oval  form,  and  is 
more  or  less  concave  in  a  direction  from  the  dorsal  toward  the  plantar 
side  of  the  foot,  while  transversely  it  is  moderately  convex. 

The  distal  face  (figure  6)  is  much  more  distinctly  saddle-shaped.  In 
some  specimens,  it  is  strongly  curved  forward  in  the  superior  region  of 
the  bone,  so  as  to  extend  through  a  considerable  arch  in  the  direction 
from  the  dorsal  toward  the  plantar  side  of  the  foot.  Transversely,  the 
articulation  is  moderately  convex  throughout. 

The  Mesocuneifoem. 

(Plate  L,  figures  7-12.) 

The  mesocuneiform  is  a  small,  somewhat  wedge-shaped  bone,  tapering 

toward  its  plantar  extremity,  and  having  its  shortest  dimension  in  the  line 

of  the  axis  of  the  foot.     It  is  much  less  oblique  than  the  coiresponding 

bone  in  the  elephant,  and  also  less  decidedly  wedge-shaped. 


THE    HIND   FEET.  159 

The  dorsal  surface  of  the  bone  (Plate  L,  figure  7)  is  rugose  and 
tuberculated,  and  tlie  jjlantar  extremity  (figure  9)  also  presents  a  rather 
prominent  protuberance. 

Of  the  lateral  faces,  the  innor  (figure  8),  turned  toward  the 
entocuneiform,  presents,  along  the  proximal  part  of  its  margin,  a  more 
or  less  elongated  facet,  for  articulation  Avith  that  bone.  The  opposite  side 
(figure  10)  turned  toward  the  ectocuneiform,  is  moderately  rough,  and 
destitute  of  any  articular  face. 

The  proximal  articular  face  (figure  11)  is  nearly  flat,  slightly  broader 
above  than  below,  and,  along  the  inner  margin,  confluent  with  the  lateral 
face  for  articulation  Avith  the  entocuneiform. 

The  distal  face  (figure  12)  is  also  nearly  flat,  and,  in  life,  supported 
in  part,  but  not  entirely,  the  second  metatarsal  bone.  The  latter  presented 
nearly  as  large  a  face  to  the  ectocuneiform,  as  to  the  mesocuneiform. 

The  following  measurements  give  the  principal  dimensions  of  this 
bone  in  two  specimens  of  JDinoceras  mirabile : 

Measurements  of  Left  Mesocuneiform.     [Dinoceras  mirabile,  No.  1210.) 

m. 
Greatest  diameter  of  mesocuneiform, 058 

Transverse  diameter, ..- .0.32 

Antero-posterior  diameters  (axial), .. .014-020 

Measurements  of  Left  Mesocuneiform.     {Dinoceras  mirabile.  No.  1208.) 

m. 

Greatest  diameter  of  mesocuneiform, .053 

Transverse  diameter, .026 

Antero-posterior  diameters  (axial), .014-.018 

The  Ectocuneifoem. 
(Plate  L,  figures  13-18.) 
The  ectocuneiform  is  triangular  in  outline,  tapering  distinctly,  and 
in  most  specimens  nearly  to  a  point,  toward  the  palmar  surface  of  the  foot. 
It  is  much  less  oblique  than  the  corresponding  bone  in  the  elephant,  and 
usually  has  the  two  distal  faces  more  distinctly  marked.  It  is  also 
proportionally  less  elongated  from  the  dorsal  toward  the  plantar  side  ot 
the  foot. 


160  DI^'UCERATA. 

The  dorsal,  or  dermal,  face  (Plate  L,  figure  13)  is  roughened  for 
ligamentary  attachroent,  and  on  the  opposite,  or  plantar,  side,  the  bone 
is  produced  into  a  more  or  less  prominent  tubercle  (figure  15).  In  the 
natural  position,  during  life,  this  elevation  was  just  back  of  the  proximal 
end  of  the  third  metatarsal. 

The  lateral  surfaces  of  the  ectocuneiform  (figures  14  and  16)  are 
moderately  roughened,  and  do  not  present  articular  surfaces  for  either 
the  mesocuneiform  on  the  inner  side,  or  for  the  cuboid  on  the  outer  side. 

The  proximal  articular  face  (figure  17)  is  nearly  flat,  or  slightly 
convex  transversely,  while,  in  a  dorso-plantar  direction,  it  may  be  more 
or  less  concave. 

The  distal  surface  (figure  18)  presents  two  confluent,  but  usually 
well  marked,  articular  surfaces.  Of  these,  the  inner  is  narrow  and  oblique, 
and  supported,  in  life,  the  outer  part  of  the  second  metatarsal.  The 
principal  articular  face  of  the  distal  end  is  nearly  flat,  sub-triangular  in 
outline,  and  narrowed  toward  the  plantar  end.  In  life,  it  supported  the 
third  metatarsal  bone. 

The  tubercle  upon  the  plantar  side  of  this  bone  differs  considerably 
in  size  and  form  (numbers  1202  and  1229).  The  degree  of  distinction 
between  the  two  distal  faces  also  varies  in  different  specimens  (numbers 
1208,  1232,  and  1199). 

The  more  important  measurements  of  the  ectocuneiform  in  four 
specimens  of  Dinoceras  are  given  below. 

Measurements  of  Right  Ectocuneiform.     [Dinoceras  mirabile,  No.  1199). 

ID- 
Greatest  diameter  of  ectocuneiform, .066 

Transverse  diameter, .045 

Antero-posterior  diameters, __. .014-026 

Diameters  of  proximal  articular  face, .030-048 

Measurements  of  Left  Ectocuneiform.     {Dinoceras  laticeps,  No.  1202.) 

m. 

Greatest  diameter  of  ectocuneiform, .060 

Transverse  diameter, .040 

Antero-posterior  diameters,  ._ .01 7-.024 

Diameters  of  proximal  articular  face, -. 033-i050 


THE   HIND   FEET.  161 

lleasia-ements  of  Left  Ectocuneiform.     {Dinoceras  mirabile,  No.  1208.) 

m. 

Greatest  diameter  of  ectocuneiform, .055 

Transverse  diameter, 035 

Antero-posterior  diameters, .016-021 

Diameters  of  proximal  articular  face, .028-039 

Measurements  of  Left  Ectocuneiform.     {Dinoceras  mirabile,  No.  1232.) 

m. 

Greatest  diameter  of  ectocuneiform, .064 

Transverse  diameter, .044 

Antero-posterior  diameters  (axial), . 014-.022 

Diameters  of  proximal  articular  face, _ 032-046 


The  Fiest  Metatarsal. 
(Plate  LI,  figures  1-6,  and  Plate  LIV,  fig-ure  2.) 

Tlie  first  metatarsal  bone  of  the  Dinocerata  is  the  shortest  and  smallest 
of  the  five,  but  is  comparatively  much  better  developed  than  in  the 
elephant. 

The  first  metatarsal  in  Dinoceras  mirabile  is  short  and  stout,  and 
strongly  roughened  on  all  sides  throughout  its  length,  as  seen  in  Plate  LI, 
figures  1-4.  As  in  the  other  metatarsals  jjreserved,  there  are  no  distinct 
indications  of  epiphysial  sutures. 

This  bone  does  not  appear,  during  life,  to  have  been  in  very  close 
relation  with  the  adjoining  metatarsal,  and  accordingly  presents,  on  its 
proximal  end  (figure  5),  only  a  single  articular  surface,  which  is  distinctly 
saddle-shaped,  and  joined  the  entocuneiform. 

The  distal  end  (figure  6)  presents  a  flattened,  and  somewhat  concave, 
face  for  the  first  phalanx,  and  immediately  below  this,  are  grooves  for  a 
pair  of  sesamoid  bones. 

The  Second  Metatarsal. 
(Plate  LI,  figures  7-12,  and  Plate  LIV,  figure  2.) 

The  second  metatarsal  in  Dinoceras  is  the  most  robust  of  the  series, 
and  is  a  short,  and  very  stout  bone. 

The    surface  of  the    shaft,    as    seen    in    Plate    LI,    figures    7-10,    is 


162  DINOCERATA. 

roughened  at  both  the  joi'oximal  and  distal  ends,  but  medially  it  is 
smoother  and  constricted,  especially  below,  where  a  large,  and  pi^ominent, 
tubercle  occupies  the  proximal  portion  of  the  under  surface  of  the  bone. 
This  tubercle  is  shown  in  figure  9,  and  also,  in  profile,  in  figures  8  and 
10,  where  it  is  seen  to  project  considerably  beyond  the  proximal  articular 
face. 

The  proximal  end  of  the  bone  (figure  11)  is  oblique  to  its  axis,  and 
presents  two  distinct  articular  faces  ;  the  larger  on  the  inner,  or  tibial, 
side  of  the  bone,  for  the  mesocuneiform,  and  the  outer,  on  the  fibular  side, 
for  the  ecto cuneiform.  The  latter  face  is  also  confluent  with  a  lateral 
facet,  Avliere  the  bone,  during  life,  touched  the  third  metatarsal.  This 
face  is  well  shown  in  figure  10. 

The  distal  end  (figure  12)  is  large,  rounded,  and  somewhat  oblique 
to  the  axis  of  the  bone.  The  articulation  for  the  phalanx  is  flattened,  but 
may  be  slightly  convex,  or,  in  a  transverse  direction,  more  or  less  concave. 
Two  well  developed  sesamoids  moved  in  broad  shallow  grooves  below, 
the  faces  for  these  bones,  taken  together,  being  about  as  large  as  that  for 
the  phalanx. 

The  Third  Metatarsal. 
(Plate  LI,  figures  13-15,  Plate  LII,  figures  1-3,  and  Plate  LIV,  figure  2.) 

The  third  metatarsal  is  of  about  the  same  length  as  the  second  and 
the  fourth,  and  is  a  little  less  robust  than  the  second. 

It  has  a  distinct  shaft,  which  is  smooth  and  constricted  medially,  but 
more  or  less  roughened  and  tubercular  toward  the  extremities,  especially 
near  the  distal  end. 

The  proximal  face  of  the  bone  (Plate  LII,  figure  2)  is  somewhat 
oblique  to  its  axis,  and  presents  a  sub-triangular  articular  face  for  the 
outer  facet  of  the  ectocuneiform.  This  facet  is  confluent,  along  its  inner 
margin,  with  a  small  lateral  face  for  union  with  the  second  metatarsal,  as 
shown  in  Plate  LI,  figure  14.  Opposite  this,  there  is  also  an  oval  face 
(Plate  LII,  figure  1)  supported  on  a  flattened  tubercle,  and  meeting, 
during  life,  a  similar  face  on  the  foiu-th  metatarsal. 


THE   limn   FEET.  Igg 

Tlie  distal  end  (Plate  Lll,  figure  3)  is  large  and  rounded,  and,  in 
some  specimens,  distinctly  oblique.  It  suj^ports  the  usual  face  for  the 
first  phalanx,  and  below,  two  shallow  grooves  for  a  pair  of  sesamoid 
bones.  The  phalangeal  face  is,  in  all  the  specimens  preserved,  distinctly, 
though  slightly,  convex  in  botli  directions. 

The  Fourth   Metatarsal. 

(Plate  LII,  figures  4-9,  and  T'late  LIV,  figure  2.) 

The  fourth  metatarsal   is  of  about  the  same  size  as  the  third,   and 

considerably  resembles  it  in  structure      Tliis  resemblance  is  much  greater 

tlian  in  the  elephant,  wliere  the  fourth  is  decidedly  shorter  than  the  third 

metatarsal. 

The  shaft  of  the  fourth  metatarsal  is  strongly  constricted  medially,  as 
seen  in  Plate  Lll,  figures  5  and  7,  and  bears  on  the  under  side,  at  the 
proximal  end,  a  large  projecting  tubercle. 

The  proximal  end  (figure  8)  bears  a  nearly  flat  articular  surface, 
sub-triangular  in  outline,  and  nearly  perpendicular  to  the  long  axis  of  the 
bone,  and  articulating,  during  life,  with  the  cuboid  bone.  This  surface 
is  confluent  on  the  outer  side  with  a  small  lateral  facet  shown  in  figure  7, 
which  corresponds  with  a  similar  face  on  the  fifth  metatarsal.  On  the 
opposite,  or  inner  side,  is  an  oval  facet  (figure  5)  articulating  in  life,  with 
a  prominent  face  on  the  third  metatarsal. 

The  distal  end  of  the  fourth  metatarsal  (figure  9)  is  but  little  oblique 
to  the  axis  of  the  bone,  and  bears  the  usual  fkces,  for  articulation  with  the 
phalanx,  and  the  sesamoids.  The  phalangeal  articulation  may  be  concave 
from  side  to  side  (number  1199),  but  is  usually  slightly  convex  in  both 
directions. 

The  Fifth  Metatarsal. 
(Plate  LII,  figures  10-15,  and  Plate  LIV,  figure  2.) 
The  fifth  metatarsal  in  Dinoceras  is  shorter  than  any  of  the  others 
except  the  first,    but  is  robust,   and   evidently  afforded  its  full  share  of 
support  to  the  foot. 


164  DINOCERATA. 

Its  surface  is  strongly  tuberculated,  especially  on  the  under  arid  outer 
sides,  as  shown  in  Plate  LII,  figures  12  and  13.  The  shaft,  being  short, 
does  not  present  a  median  constriction,  as  in  the  three  preceding 
metatarsals. 

The  proximal  end  (figure  14)  bears  a  comparatively  small  articular 
face  for  support  on  the  cuboid  bone.  This  face  is  nearly  flat,  and 
somewhat  quadrangular  in  outline,  and  is  confluent,  on  the  inner  margin, 
with  a  small  lateral  face  for  the  fourth  metatarsal,  as  seen  in  figure  11. 
The  proximal  articular  face  is  nearly  at  right  angles  to  the  axis  of 
the  bone. 

The  distal  face  (figure  15)  for  the  proximal  phalanx  is  turned  strongly 
outward,  and  is  more  or  less  concave.  The  sesamoid  grooves,  also,  look 
strongly  outward,  and  the  inner  is  larger  than  the  outer. 

The  Phalanges. 
(Plates  LII-LVI.) 
The  phalanges  of  the  hind  foot  in  the  Binocerata  are  very  similar  to 
those  of  the  fore  foot,  although  smaller,  and  hence  need  no  detailed 
description.  In  Plate  LIII,  these  bones  are  well  represented,  and  with 
them,  some  of  the  sesamoid  bones  of  the  same  feet.  In  Plate  LIV,  figure 
2,  the  phalanges  are  shown  in  position,  and  other  view^s  of  them  may  be 
seen  in  the  two  restorations  on  Plates  LV  and  LVI. 


CHAPTER    XTIL 


RESTORATIONS  OF  DINOCERAS  AND  TINOCERAS. 

(Plates  LV  and  LVI.) 

The  preceding-  chapters  of  this  memoir,  and  the  illustrations  given  in 
Plates  I-LIV,  will  make  known  to  anatomists  nearly  all  the  important 
cliaracters  in  the  skeleton  of  the  gigantic  mammals  of  the  order  Dinocerata. 
In  Plate  LV,  a  restoration  is  given  of  Dinoceras  mirabile,  the  type  of  the 
group,  and,  in  Plate  LVI,  one  also  of  Tinoceras  ingens,  a  characteristic, 
and  more  specialized  form  of  an  allied  genus. 

The  remains  available  for  these  restorations  consist  of  portions  of 
more  than  two  hundred  individuals  of  the  Dinocerata.  As  none  of  the 
skeletons  of  the  species  here  represented  were  complete  when  found,  it 
has  been  necessary  to  use,  in  both  restorations,  the  bones  of  other 
individuals  which  could  not  be  distinguished  from  the  type  specimens. 
Some  of  these  bones  may,  perhaps,  belong  to  allied  forms,  but  it  is 
believed  that  the  restorations,  as  here  given,  fairly  represent  the  skeletons 
of  the  species  named. 

In  the  restoration  of  Dinoceras  mirabile  on  Plate  LV,  the  remains  of 
the  type  specimen  of  the  species,  a  fully  adult,  but  not  old  individual, 
have  been  used  for  the  more  important  parts,  and  the  remaining  portions 
taken  from  other  individuals.     This  restoration  is  one-eighth  natural  size. 

165 


166  DINOCERATA. 

The  animal  is  repi-esented  as  walking,  and  the  position  of  the  head, 
and  the  feet,  has  been  cliosen  to  show,  to  the  best  advantage,  these 
portions  of  the  skeleton  as  they  were  in  life.  In  this  restoration,  only 
those  230rtions  are  shaded  which  are  represented  by  actual  specimens  in 
the  Yale  Museum.  The  parts  in  outline  are  either  wanting,  or  so  poorly 
preserved  that  only  their  main  features  can  be  given  with  accuracy. 

In  the  restoration  of  Tinoceras  ingens,  Plate  LVI,  the  animal  is 
represented  one-sixth  natural  size,  and  standing  at  rest.  The  position 
here  chosen  shows  the  massive  and  majestic  form  of  one  of  the  largest 
individuals  of  this  remarkable  group.  Here,  likewise,  the  shaded  portions 
are  represented  by  specimens  in  the  Yale  Museum.  Some  of  these  bones 
were  used  also  in  the  first  restoration. 

In  comparing  Dinoceras,  as  here  restored,  with  some  of  the  largest 
ungulate  mammals  of  the  present  day,  a  certain  resemblance  to  the 
rhinoceros  on  the  one  hand,  and  to  the  elephant  on  the  other,  will 
naturally  suggest  itself.  In  size  and  proportions,  JDinoceras  was 
intermediate  between  these  two  existing  animals,  and  in  various  points  of 
its  structiu-e,  it  resembled  the  one  quite  as  much  as  the  other.  In  still 
other  features,  JDinoceras  resembled  the  hippopotamus,  and  its  affinities 
with  the  groups  represented  by  these  three  types  will  be  discussed  in 
the  succeeding  chapter. 

In  its  stature  and  movements,  Binoceras  probably  resembled  the 
elephant  as  much  as  any  other  existing  form.  Its  remarkable  skull, 
longer  neck,  and  more  bent  fore  limbs,  gave  it,  however,  a  very  diiferent 
appearance  from  any  known  Proboscidian.  The  high  protuberances  on 
the  head,  the  long  trenchant  canine  tusks,  and  the  peculiar  lower  jaw 
modified  for  their  protection,  are  features  seen  together  only  in  this  group. 

The  neck  was  long  enough  to  permit  the  head  to  reach  the  ground, 
and  hence  a  proboscis  was  quite  unnecessary.  The  horizontal  narial 
opening,  the  long  overhanging  nasal  bones,  and  the  well  developed 
turbinal  bones,  are  likewise  proof  positive  against  the  presence  of  such 
an  organ.  There  is  some  evidence  of  a  thick  flexible  lip,  resembling, 
perhaps,  that  of  the  existing  rhinoceros. 


RESTORATIONS.  167 

The  remarkably  small  brain,  and  tlie  heavy  massive  limbs,  indicate 
a  dull,  slow-moving-  animal,  little  fitted  to  withstand  sudden  changes  in  its 
environment,  and  hence  it  did  not  survive  the  alterations  of  climate  with 
which  the  Eocene  period  closed. 

That  the  Dinocerata  were  very  abundant  for  a  long  time  during  the 
middle  Eocene  is  proved,  concliisively,  by  their  numerous  remains  in 
dejDosits  of  this  age.  That  the  animals  lived  in  herds  is  also  suggested  by 
the  jjosition  in  which  the  remains  are  found.  Their  favorite  resorts  would 
seem  to  have  been  around  the  borders  of  the  g'reat  Eocene  tropical  lake 
described  in  the  Introduction  of  the  present  volume.  Here,  they  found 
an  abundance  of  food,  which  was  evidently  the  soft  succulent  vegetation 
which  flourished,  then  as  now,  in  such  localities. 

In  Tinoceras,  represented  in  Plate  LVI,  we  have  the  skeleton  of  a 
larger,  and  still  more  imposing  animal,  but  with  essentially  the  same 
characteristics.  The  remains  of  this  genus  are  found  in  the  same 
lake-basin  as  those  of  Dinoceras,  but  at  a  higher  level,  and  the  evidence 
is  clear  that  Tinoceras  is  a  later,  and  more  specialized  form. 

Both  the  animals  chosen  for  these  two  restorations  were  evidently 
males,  as  shown  by  the  lofty  protuberances,  or  horn-cores,  on  the  skull, 
and  the  powerful  canine  tusks.  In  the  females,  these  parts  are  but 
feebly  developed,  as  seen  in  the  specimens  described  in  the  preceding 
chapters.  The  individuals  here  restored  were  certainly  thrice-armed,  and 
well  fitted  to  protect  themselves,  and  their  weaker  associates,  from  any 
of  their  Eocene  enemies. 

The  exact  form  and  nature  of  the  off"ensive  weapons  which  surmoitnted 
the  head  of  the  Dinocerata  cannot,  at  present,  be  determined  with  certainty. 
That  the  paired  osseous  elevations  on  the  skull  in  all  the  known  species 
of  this  group  did  not  support  the  kind  of  horns  seen  in  the  typical 
Ruminants  is  evident  from  their  external  surface,  which  lacks  the  vascular 
grooves  so  distinct  on  the  horn-cores  of  those  animals. 


168  DINOCERATA. 

Possibly  the  Dinocerata  may  have  been  armed  with  horns  similar  to 
those  seen  in  the  American  antelope  (AntUocapra)^  since,  in  this  animal, 
the  horn-cores  are  even  smoother  than  in  the  order  here  described.  More 
probably,  however,  the  bony  protuberances  on  the  skull  were  covered 
with  bosses  of  thick  skin,  hard  enough  to  be  effective  in  combat. 
Evidence  of  such  contests  has  apparently  been  recorded  in  the  injuries 
to  the  horn-cores  of  some  individuals,  received  during  life.  None  of  the 
covering  of  these  elevations,  or  horn-cores,  has,  of  course,  been  preserved ; 
yet  a  fortunate  discovery  may,  perhaps,  reveal  their  nature  by  the  form 
of  a  natural  cast,  as  the  eye-ball  of  the  Oreodon  is  sometimes  thus  clearly 
indicated  in  the  fine  Miocene  matrix  which  envelops  these  animals. 

The  short  robust  feet  of  the  Dinocerata  were  doubtless  covered  belosv 
with  a  thick  pad,  as  in  the  elephant,  since  the  whole  under  side  of  the 
foot  clearly  indicates  such  a  protection.  No  portion  of  this  covering  has 
been  preserved  in  any  of  the  known  specimens,  and  no  foot-prints, 
indicating  its  form,  have  been  discovered  in  the  Eocene  deposits  in  which 
the  Dinocerata  were  entombed. 

The  size  of  Tinoceras  ingens,  as  he  stood  in  the  flesh,  was  about 
twelve  feet  (3.65  M.)  in  length,  or  sixteen  (4.9  M.),  measured  from  the 
nose  to  the  end  of  the  tail.  The  height  to  the  top  of  the  back  was  about 
six  and  one-half  feet  (2  M.),  and  the  width  across  the  hips  about  five 
feet  (1.5  M.).  The  weight,  judging  from  that  of  existing  mammals,  was 
at  least  six  thousand  pounds  (2.75  T.). 

Dinoceras  mirabile  was  about  one-fifth  smaller.  The  neck  was 
longer,  but,  in  other  respects,-  the  proportions  were  nearly  the  same. 

Dinoceras  mirabile  when  standing  at  rest  would  have  a  general 
resemblance  to  a  very  large  rhinoceros.  When  walking,  the  movement 
of  the  hind  limbs  would  at  once  suggest  the  elephant,  as  we  know  it 
to-day.  The  movement  of  the  head  in  Dinoceras  was  much  freer  than 
that  in  the  elephant,  as  the  neck  was  longer,  and  arched  upward,  and 
the  vertebrse  admitted  of  much  more  freedom  of  motion.  The  eye  was 
small,  and  deep  set,  as  in  the  rhinoceros.  The  head  of  Dinoceras  must 
have  had  some  resemblance  to  that  of  the  hippopotamus,  but  was  very 
different  from  that  of  any  known  animal,  living  or  extinct. 


CHAPTER     XIY. 


CONCLUSION. 
(Plates  LIV-LVI,  and  woodcuts  147-169,  below.) 

The  more  important  characters  of.  the  Dinocerata,  so  far  as  known, 
have  been  given  in  the  preceding  chapters,  and  the  anatomist  can  now 
form  a  fair  picture  of  characteristic  members  of  the  group.  It  remains  to 
consider  what  the  relations  of  this  peculiar  group  are  to  the  nearest  allied 
forms,  and,  especially,  to  ascertain,  if  possible,  whether  the  evidence 
before  us  throws  any  light  on  the  origin  of  the  Dinocerata,  and,  more 
remotely,  on  the   genealogy  of  all  Ungulate  Mammals. 

The  oldest  known  mammals  are  of  Triassic  age,  but  the  few 
specimens  yet  discovered  give  little  information  as  to  the  primitive  forms 
of  this  class.  During  Jurassic  time,  mammals  were  very  abundant,  and 
deposits  of  this  age  now  offer  a  promising  field  for  exploration. 

Of  Triassic  and  Jurassic  mammals,  the  author  has  studied  with  some 
care  every  known  specimen  in  this  country,  and  in  Europe,  and  some  of 
the  conclusions  here  given  are  based  upon  this  examination.  Special 
attention  has  been  paid  to  the  Jurassic  mammals  of  this  country,  which 
the  author  first  discovered  in  the  Rocky  Mountain  region.  Remains  of 
neai-ly  four  hundred  individuals,  representing  many  genera  and  species, 
have  already  been  secured,  and  their  investigation  promises  to  clear  up 
many  doubtful  points  in  the  early  history  of  this  class. 

No  Cretaceous  mammals  are  known,  and  it  is  this  great  break  in  the 
series  of  ancient  forms  that  renders  any  satisfactory  classification  of  the 
class,  living  and  extinct,  at  present  impossible. 

22  169 


170  DINOCERATA. 

At  the  very  base  of  the  Tertiary,  we  find  the  class  of  Mammals  well 
represented  by  many  widely  separated  groups,  which  point  back  to  a 
common  ancestry,  only  in  a  very  remote  period. 

Our  present  knowledge  of  the  Mammalia,  living  and  extinct,  clearly 
indicates  that  they  must  go  back  at  least  to  the  Permian.  The  generalized 
mammal  of  that  period,  or  of  still  earlier  time,  was  probably  quite  small, 
and,  in  many  respects,  like  an  Insectivor.  This  primitive  type  would 
naturally  possess  all  the  general  characters  found  in  later  forms  in  the 
various  orders  of  mammals.  The  characters  therefore  we  should  expect  to 
find  in  this  ancestral  mammal  would  be  essentially  the  following : 

(1.)  Brain,  small  and  smooth. 

(2.)  Teeth,  more  than  forty-four. 

(3.)  Vertebrae,  biconcave. 

(4.)  Trunk  vertebrae,  more  than  thirty. 

(5.)  Sacral  vertebrae,  separate. 

(6.)  Intercentral  bones. 

(7.)  Chevron  bones. 

(8.)  Cervical  ribs,  free. 

(9.)  Clavicles,  free. 
(10.)  Coracoids,  free. 
(11.)  Sternal  bones,  flat. 

(12.)  Humerus  with  supra-condylar  foramen. 
(13.)  ■  Feet,  plantigrade. 
(14.)  Five  digits  in  manus  and  in  pes. 
(15.)  Carpal  and  tarsal  bones  not  interlocking. 
(16.)  Separate  central  bone  in  carpus. 
(17.)  Pelvic  bones,  separate. 
(18.)  Epipubic  bones. 
(19.)  Acetabular  bones. 
(20.)  Femur  with  third  trochanter. 
(21.)  Three  bones  in  first  tarsal  row. 
(22.)  Astragalus,  flat. 
(23.)  Fibula  articulating  with  calcaneum. 


CONCLUSION.  171 

This  generalized  mammal  would  belong  to  the  group  named 
Hypotheria  by  Huxley,  who  has  laid  a  sure  foundation  for  investigation  in 
this  line  of  research. 

Genealogy  of  Ungulates. 

From  this  primitive  type  of  mammal,  a  special  line  apparently  led  off 
through  the  Triassic  and  Jurassic  to  the  Cretaceous,  where  it  formed  a 
well  marked  group,  which  may  be  called  tlie  Protungulata,  tlie  probable 
ancestors  of  all  succeeding  Ungulate  Mammals. 

The  characters  of  this  type  would  be  somewhat  as  follows : 

(1.)  Brain,  small  and  smooth. 

(2.)  Teeth,  forty-four  or  more. 

(3.)  No  frontal  appendages. 

(4.)  Odontoid  process,  conical. 

(5.)  Vertebra;,  flat. 

(6.)  Trunk  vertebrse,  thirty  or  more. 

(7.)  Chevron  bones. 

(8.)  Clavicles  present. 

(9.)  Sternal  bones,  flat. 
(10.)  Humerus  with  supra-condylar  foramen. 
(11.)  Feet,  plantigrade. 
(12.)  Five  digits  in  manus  and  in- pes. 
(13.),  Carpal  and  tarsal  bones  not  interlocking. 
(14.)  Separate  central  bone  in  carpus. 
(15.)  Femur  with  third  trochanter. 
(16.)  Three  bones  in  first  tarsal  row. 
(17.)  Astragalus,  flat. 
(18.)   Fibula  articulating  with  calcaneum. 

From  this  generalized  ungulate,  the  skeleton  of  which  we  now  know 
almost  as  well  apparently  as  if  we  had  it  before  us,  a  direct  line  would 
appear  to  have  continued  up  to  the  present  day,  and  be  represented  by 
the  living  Hyrax.  Several  divergent  lines  j^assed  off  probably  from  the 
same  stem,  and  three  of  these  have  continued  to  the  present  time,  the 
survivors  beino-  the  Prohoscidea,  the  Artiodadyla,  and  the  Perissodactyla. 


172  DINOCERATA. 

The  Proboscidian  line  apparently  went  off  from  the  main  ungulate 
stem  in  the  Cretaceous.  One  branch  ended  in  the  later  Pliocene  in 
Dinotherium ;  another,  in  Mastodon ;  while  the  geniis  Elephas  alone 
survives,  to  represent  this  old  group. 

Another  strong  branch,  represented  by  a  group  which  may  be  called 
the  Holodactyla,  probably  also  led  off  in  the  Cretaceous,  and  its  typical 
members,  at  least,  had  the  following  general  characters : 

(1.)  Brain,  small  and  nearly  smooth. 

(2.)  Teeth,  forty -four. 

(3.)  Post  glenoid  process. 

(4.)  Odontoid  process,  conical. 

(5.)  Vertebrae,  flat. 

(6.)  Trunk  vertebrae,  twenty-three  or  more. 

(7.)  Chevron  bones. 

(8.)  Pelvic  bones,  firmly  united. 

(9.)  Femur  with  third  trochanter. 

(10.)  Ulna  and  fibula,  complete. 

(11.)  Fibula  articulating  with  calcaneum. 

(12.)  Five  digits  in  manus  and  in  pes. 

(13.)  Carpal  and  tarsal  bones  more  or  less  interlocking. 

(14.)  Astragalus,  nearly  or  quite  flat. 

This  line  evidently  divided  near  the  base  of  the  Eocene  into  the 
great  groups  of  Perissodactyls  and  Artiodactyls,  each  with  many 
off-shoots,  and  still  existing.  The  former  are  now  on  the  decline,  and 
have  but  three  living  representatives,  the  horse,  the  tapir,  and  the 
rhinoceros. 

One  off-set  from  the  Perissodactyl  line  separated  near  the  top  of  the 
Eocene,  where  it  is  represented  by  JDiplacodon,  and  perhaps  ended  in  the 
extinct  Brontotherium,  of  the  lower  Miocene,  although  this  line  may  have 
been  continued  somewhat  later  in  the  genus  CJialicothcriiim. 

From  the  Artiodactyl  line,  a  peculiar  group  branched  off  in  the  early 
Eocene,  and  in  the  Miocene  was  represented  by  Oreodon  and  allied  genera, 
and  by  later  forms  in  the  Pliocene.  The  Artiodactyls,  now  the  dominant 
ungulates,  have  numerous  families,  and  many  living  genera  and  species. 


CONCLUSIOK 


173 


Another  order,  also,  which  may  be  termed  the  Amblydactyla,  passed 
off  apparently  from  the  main  imgulate  stem  in  the  Cretaceous,  and  became 
extinct  in  the  Eocene.  One  branch  terminated  in  Corijpliodon,  in  the  lower 
Eocene,  and  the  other,  represented  by  the  Dinocerata,  here  described,  came 
to  an  end  in  the  Middle  Eocene. 

In  figure  147,  below,  a  diagram  is  given,  which  shows  graphically 
these  lines  of  descent,  and  the  most  probable  genealogy  of  modern 
Ungulates.  The  diagram,  being  on  a  plane,  can  only  indicate  the  general 
position  of  these  divergent  lines. 


FiGDRE  147. — Diagram  to  illustrate  the  genealogy  of  Ungulate  Mammals. 

A  comparison  of  this  diagram  with,  the  section  on  page  7  of  this 
volume  will  make  clear  the  special  geological  horizons  of  each  group  here 
referred  to. 

The  Hyracoidea  are  represented  by  tlie  existing  Hyrax,  and  no  fossil 
remains  of  the  group  are  known.  The  principal  characters  of  the  o-rder 
are  as  follows : 


174  DINOCERATA, 

(1.)  Brain,  large  and  convoluted. 

(2.)  Canines,  absent. 

(3.)  Incisor  tusks. 

(4.)  Maxillo-turbinal  bones. 

(5.)  Premolar  and  molar  teeth,  similar. 

(6.)  Malar  bone  articulating  with  lower  jaw, 

(7.)  Alisphenoid  canal. 

(8.)  Post-glenoid  process. 

(9.)  Odontoid  process,  conical. 
(10.)  Cervical  vertebrae,  convexo-concave. 
(11.)  Trunk  vertebrae,  twenty-nine  or  more. 
(12.)  Scapula,  spatulate. 
(13.)  Iliac  bones,  parallel. 
(14.)  Femur  with  third  trochanter. 
(15.)  Femur  and  tibia  not  in  line. 
(16.)  Ulna  and  fibula,  complete. 
(17.)  Feet,  plantigrade. 
(18.)  Axis  of  foot  through  third  digit. 
(19.)  Carpals  and  tarsals  not  interlocking. 
(20.)  Central  bone  in  carpus.  ^ 

(21.)  Three  bones  in  first  tarsal  row. 
(22.)  Astragalus,  grooved. 

The  Proboscidians,  recent  and  extinct,  may  all  be  placed  in  a  single 
order,  with  the  following  distinctive  characters  : 

(1.)  Brain,  large  and  convoluted. 

(2.)  Canines,  absent. 

(3.)  Incisor  tusks. 

(4.)  Maxillo-turbinal  bones,  rudimentary. 

(5.)  Malar  bone  forming  middle  of  zygomatic  arch. 

(6.)  Post-glenoid  process,  absent. 

(7.)  Alisphenoid  canal. 

(8.)  Odontoid  process,  conical. 


CONCLUSION.  1T5. 

(9.)  Vertebrse,  flat. 
(10.)  Scapula,  acuminate. 
(11.)  Sternal  bones,  flat. 
(12.)  Iliac  bones,  transverse. 
(13.)  Femur  and  tibia  in  line. 
(14.)  Ulna  and  tiljula,  complete. 
(15.)   Femur  without  third  trochanter 
(16.)  Feet,  plantigrade. 
(17.)  Axis  of  foot  through  third  digit. 
(18.)  Five  digits  in  manus  and  pes. 
(19.)  Two  bones  in  first  tarsal  row. 
(20.)  Carpals  and  tarsals,  slightly  interlocking. 
(21.)  Astragalus,  flat. 
(22.)  Fibula  articulating  with  calcaneum. 

The  Holodadijla  were  the  direct  ancestors  of  the  great  group  to  which 
both  the  Perissodactyls  and  Artiodactyls,  living  and  extinct,  belonged. 
The  two  latter  form  together  a  well  marked  order,  which  may  be  called 
the  Clinodactyla.     Their  more  important  characters  are  as  follows : 

(1.)  Brain,  moderate  in  size,  and  convoluted. 

(2.)  Lower  canines. 

(3.)  Maxillo-turbinal  bones. 

(4.)  Malar  bone  forming  front  of  zygomatic  arch. 

(5.)  Post-glenoid  process. 

(6.)  Cervical  vertebrse,  more  or  less  convexo-concave. 

(7.)  Trunk  vertebrse,  not  more  than  twenty-three. 

(8.)  Scapula,  si^atulate. 

(9.)  Iliac  bones,  parallel. 
(10.)  Femur  and  tibia  not  in  line. 
(11.)  Feet,  digitigrade. 

(12.)  Carpals  and  tarsals,  strongly  interlocking. 
(13.)  Central  bone,  absent. 
(14.)  Scaphoid  articulating  with  magnum. 
(15.)  Astragalus,  grooved. 


176  DINOCERATA. 

Returning  now  to  the  AmUydactyla,  or  the  group  from  which  the 
Dinocerata  were  evidently  derived,  and  to  whicli  they  belong,  we  may 
safely  assign  to  them  general  characters  as  follows : 

(1.)  Brain,  small  and  smooth. 

(2.)  Teeth,  not  more  than  forty-four. 

(3.)  Post-glenoid  process. 

(4.)  Odontoid  process,  conical. 

(5.)  Cervical  vertebrfe,  flat. 

(6.)  Trunk  vertebrae,  twenty-three  or  more. 

(7.)  Scapula,  acuminate. 
,(8.)  Feet,  plantigrade. 

(9.)  Five  digits  in  manus  and  in  pes. 
(10.)  Axis  of  foot  through  third  digit. 
(11.)  Carpal  and  tarsal  bones,  somewhat  interlocking. 
(12.)  Three  bones  in  first  tarsal  row. 
(13.)  Astragalus,  flat. 
(14.)  Fibula  articulating  with  calcaneum. 
(15.)  Cuboid  articulating  with  astragalus. 

From  this  group  came  off,  evidently  in  the  late  Cretaceous,  first  the 
Coryphodontia,  having  nearly  all  the  above  characters,  and  becoming 
extinct  in  the  early  Eocene.  The  Binocerata  probably  branched  off  about 
the  same  time,  and  survived  to  the  Middle  Eocene,  thus  becoming  much 
more  specialized  before  their  extinction. 

Classification  of  Ungulates. 

Accepting  this  general  view  of  the  origin  of  the  Ungulates,  living  and 
extinct,  their  classification  has  been  outlined  in  the  diagram  on  page  173, 
and  little  more  can  now  be  done. 

The  attempts  hitherto  made  to  give  a  detailed  classification  of  all  the 
Mammalia,  living  and  extinct,  have  signally  failed,  mainly  because  only  a 
small  part  of  even  the  extinct  forms  now  known  were  included,  and  almost 
every  new  discovery  tended  to  break  down  the  definitions  so  systematically 


CONCLUSION.  177 

recorded.  The  time  for  such  an  exhaustive  classification  has  not  yet 
arrived,  and  all  that  can  be  safely  ventured  upon  in  the  present  state  of 
knowledge  is  to  indicate  the  main  gi-oups,  and  their  affinities,  and  await 
future  discoveries. 

Excluding  the  aberrant  aquatic  Sirenians,  now  regarded  as  of  ungulate 
ancestry,  and  leaving  out  also  Toxodon  and  other  little  known  extinct 
forms,  the  Ungulate  IMammals  may  then  be  arranged  in  natural  groups, 
as  follows : 

CLASS   MAMMALIA. 

Sub-Class    MONODELPHIA. 

Super-Order  Ungulata. 

(L)  Order  Hyracoidea. 
(2.)  Order  Proboscidea. 

(3.)  Order  Amblydactyla  \  Di"ocerata.    ^ 
_      •<         -I      (  Corypliodontia. 

r A  \   r\   -\      r^^^      i     j.  ^     S  Mesaxonia  (Perissodactyla). 
(4.)  Order  Clmodactyla  {  ^  .     /.     •    i         ^\ 

(  raraxoma  (Artiodactyla). 

Before  proceeding  to  discuss  the  relations  of  the  Dinocerata  to  allied 
forms,  it  is  important  to  first  consider  the  relative  value  of  the  characters 
they  share  with  these  allies,  and  with  groups  still  more  remote. 

The  characters  found  in  existing  mammals,  and,  to  a  great  extent,  in 
the  extinct  forms  from  the  Tertiary  to  the  present  time,  are  clearly  of  two 
kinds ;  general  characters,  derived  from  ancestral  forms,  and  special 
characters,  acquired  in  adaptation  to  their  environment.  Some  of  the 
latter  may  be  negative  characters,  acquired  by  the  disuse,  or  loss,  of 
parts  once  advantageous. 

The  first  series  of  characters  are  of  most  importance,  as  they  indicate 
a  genetic  connection,  perhaps  remote,  with  the  different  groups  that  share 
them.  Special  characters,  on  the  other  hand,  however  closely  they  may 
correspond  in  different  groups,  do  not  necessarily  indicate  affinities,  but 
may  have  been  acquired  by  adaptation  to  peculiar  surroundings,  in  groups 
quite  distinct  from  each  other. 

23 


178  DmOCERATA. 

These  facts  lie  at  the  foundation  of  classification,  and  it  is  only  by 
keeping  the  two  series  of  characters  separate,  that  the  true  relationship 
between  different  groups  of  animals  can  be  made  out,  and  their  genealogy 
indicated  with  any  probability. 

Bearing  this  in  mind  in  considering  the  Dinocerata,  we  must  first  seek 
to  ascertain  what  general  characters  they  have  inherited  from  ancestral 
forms,  and  next  what  special  characters  they  have  since  acquired.  The 
relation  of  the  group  to  the  orders  of  existing  Ungulates  will  then  be 
indicated  by  ascertaining  what  characters,  derived  from  a  common 
ancestry,  they  share  with  each  other,  and  what  special  characters,  due, 
perhaps,  to  influences  of  similar  nature,  they  possess  in  common. 

We  have  seen  that  the  primitive  Mammals  {Hypotherid)  must  have 
possessed  a  large  number  of  general  characters,  some  of  which  have 
already  been  given  in  the  list  on  page  170.  The  primitive  Ungulates 
(Protungitlata),  starting  off  on  a  particular  line  from  the  preceding  type, 
would  natui'ally  retain  nearly  all  these  general  characters,  as  indicated 
in  the  list  on  page  171.  Each  of  the  great  branches  that  passed  off  from 
this  parent  stem  retained  a  certain  number  of  these  primal  characters,  and 
some  of  them  we  find  in  the  Ungulates  of  to-day. 

The  characters  jDOssessed  by  the  Holodactyla  were  most  of  them  still 
the  ancestral  features,  and  the  Amblydacti/la,  on  the  line  toward  the 
Dinocerata,  shared  many  of  the  same  characters. 

The  Dinocerata,  representing  a  fm-ther  stage  of  progress,  had  still  as 
their  inheritance  a  number  of  persistent  general  characters.  Some  of 
these  characters  are  the  following : 

(1.)  Brain,  small  and  smooth. 

(2.)  Orbit  open  behind. 

(3.)  Post-glenoid  process. 

(4.)  Alisphenoid  canal. 

(5.)  Vertebrse,  flat. 

(6.)  Odontoid  process,  conical. 

(7.)  Sternum,  flat. 

(8.)  Feet,  plantigrade. 


CONCLUSION.  179 

(9.)  Five  digits  in  inanus  and  in  pes. 
(10.)  Three  bones  in  first  tarsal  row. 
(11.)  Astragalus,  flat. 

The  si^ecialized  characters  of  the  Bimcerafa,  acquired,  doubtless,  since 
this  line  separated  from  the  Protungulata,  are  as  follows : 
(1.)  Pre-nasal  bones. 
(2.)  No  upper  incisors. 
(3.)  Canine  tusks. 

(4.)  Skull  surmounted  with  protuberances. 
(5.)  Condyle  of  lower  jaw,  posterior. 
(6.)  Pendent  processes  on  lower  jaw. 
(7.)  Iliac  bones,  transverse. 
(8.)  Femur  and  tibia  in  line. 

If  we  now  compare  the  Binocerata  with  the   Corypliodontia,  we  find 
they  agree  in  the  following  characters : 

(1.)  Brain,  small,  and  nearly  smooth. 

(2.)   Greneral  form  of  teeth. 

(3.)  Temporal  fossae,  widely  separated. 

(4.)  Post-glenoid  process. 

(5.)  Odontoid  process,  conical. 

(6.)  Vertebrae,  flat. 

(7.)  Scapula,  acuminate. 

(8.)  Feet,  plantigrade. 

(9.)  Five  digits  in  manus  and  in  pes. 
(10.)  Axis  of  foot  through  third  digit. 
(11.)  Three  bones  in  first  tarsal  row. 
(12.)  Astragalus,  flat. 
(13.)  Fibula  articulating  with  calcaneum. 
(14.)  Cuboid  articulating  with  astragalus. 

In  compai-ing  the  Binocerata  with  living  forms,  and  first  with  the 
Proboscidians,  we  find  certain  characters  common  to  both,  some  of  which 
at  least,  are  general  features,  derived  from  a  remote  common  ancestry. 
The  more  important  of  tliese  characters  are  as  follows : 


180  DINOCERATA. 

(1.)  Alisplienoid  canal. 

(2  )  Odontoid  process,  conical. 

(3.)  Vertebra3,  flat. 

(4.)  Scapula,  acuminate. 

(5.)  Sternal  bones,  flat. 

(6.)  Iliac  bones,  transverse. 

(7.)  Fibula,  complete. 

(8.)  Femur  and  tibia  in  line. 

(9.)  Femur  without  third  trochanter. 
(10.)  Five  digits  in  manus  and  pes. 
(11.)  Axis  of  foot  through  third  digit. 
(12.)  Fibula  articulating  with  calcaneum. 
(13.)  Astragalus,  flat. 
(14.)  Digits  enclosed  in  a  common  integument 

The  characters  found  in  the  Dinocerata,  and  not  in  the  existing 
Prohoscidea  are  more  important,  and  more  numerous.  Among  these 
characters  are  the  following : 

(1.)  Brain,  small  and  smooth. 

(2.)  No  upper  incisors. 

(3.)  Canine  teeth  above  and  below. 

(4.)  Anterior  nares  in  front. 

(5.)  Pre-nasal  bones. 

(6.)  Maxillo-turbinal  bones,  well  developed. 

(7.)  Skull  surmounted  with  protuberances.. 

(8.)  Premaxillaries  not  meeting  frontals. 

(9.)  Malar  bone  forming  anterior  part  of  zygomatic  arch. 
(10.)  Post-glenoid  process. 
(11.)  Condyle  of  lower  jaw,  posterior. 
(12.)  Neck  of  medium  length. 
(13.)  Three  bones  in  first  tarsal  row. 
(14.)  Astragalus  articulating  with  cuboid. 


CONCLUSION.  181. 

If  now  we  compare  the  Dlnocerata  with  the  Perissodactyls,  ue  find 
an  agreement  in  the  following  characters : 

(1.)  Premolar  and  molar  teeth  similar  in  form. 

(2.)  Nasal  bones  expanding  posteriorly. 

(3.)  Malar  bone  forming  front  of  z3'gomatic  arch. 

(4.)  Alisphenoid  canal. 

(5  )  Posterior  nares  between  last  molars. 

(6.)  Post-glenoid  process. 

(7.)  Carpal  and  tarsal  bones,  more  or  less  interlocking. 

(8.)  Axis  of  foot  through  third  digit. 

(9.)  Astragalus  articulating  with  cuboid. 

With  the    typical    Artiodactyls,   the    Dlnocerata   have    the    following' 
characters  in  common : 

(1.)  Cranial  protuberances  in  pairs. 
(2.)  No  upper  incisors. 

(3.)  Premaxillary  bones  uniting  with  maxillaries  and  nasals. 
(4.)  Premaxillaries  with  palatine  plates. 
(5.)  Lower  incisors  and  canine  in  continuous  series. 
(6.)  Sternal  bones,  flat. 
(7.)  Femur  without  third  trochanter. 
(8.)  Carpal  and  tarsal  bones,  more  or  less  interlocking. 
(9.)  Fibula  articulating  with  calcaueum. 
(10).  Astragalus  articulating  with  cuboid. 

Modification  of  the  Ungulate  Foot. 

The  characters  of  most  importance  in  Ungulate  Mammals  are  found 
in  the  teeth,  the  brain,  and  the  feet.  The  last  are  of  special  interest  in 
tlie  present  connection,  as  they  mark  the  stages  of  development  in  each 
group  from  the  primitive  Ungulates  to  the  highly  modified  forms  existing 
to-day.  A  brief  statement  of  this  development  will  make  more  clear  the 
relation  of  the  Binocerata  to  other  groups  of  Ungulates,  with  which  we 
have  already  compared  them. 


182  DINOCERATA. 

The  most  generalized  limbs  in  any  vertebrates,  above  the  class  of 
fishes,  are  seen  in  some  of  the  extinct  aquatic  reptiles,  especially  in  forms 
allied  to  Ichthyosaurus.  Here,  as  the  author  has  shown,  i  we  may  find  in 
one  group, 

(1.)  Each  limb  a  simple  fin,  or  paddle, 

(2.)  Fore  and  hind  limbs  identical  in  structure, 

(3.)  Axis  of  limb  through  intermedial  bone  and  third  digit, 

(4.)  Single  bone  (humerus  or  femur)  in  propodial,  or  first,  segment, 

(5.)  Three   bones,    including   intermedial,    in   epipodial,    or   second, 

segment, 
(6.)  Mesopodial  bones  (carpals  or  tarsals)  circular  disks, 
(7.)  Number  of  digits  six  or  more, 
(8.)  Metapodial  bones  and  phalanges  circular  disks, 
(9.)  Phalanges,  very  numerous. 

This  is  a  primitive  aquatic  limb,  flexible,  but  without  joints,  and 
adapted  to  swimming  only.  An  example  of  such  a  limb  is  seen  in 
figure  148,  below. 

For  progression  both  in  water  and  on  wet  ground,  an  essential 
modification  of  such  a  limb  would  be  required,  and  a  type  seen  in  some 
of  the  living  reptiles  would  gradually  be  developed.  This  limb  woidd 
be  jointed  at  two  points,  and  have  five  digits,  with  the  axis  through  the 
middle  one.  The  foot  in  this  limb  would  be  very  similar  to  the 
generalized  foot  of  the  primitive  Mammal,  and  may  here  be  taken  as  its 
representative.     An  example  of  such  a  foot  is  shown  in  figure  149. 

In  the  true  Ungulate  Mammals,  the  modifications  of  the  feet  have 
undoubtedly  taken  place  very  nearly  in  the  following  manner : 

(1.)  The  primitive  Ungidates  (Protungulata)  must  have  had 
plantigrade,  pentadactyl,  feet,  with  the  carpals  and  tarsals  not  interlocking, 
either  with  the  metapodial  bones,  or  with  their  own  adjoining  series. 
This  would  give  a  weak  foot,  adapted  especially  to  progression  in   soft 

'  Limbs  of  Sauranodon,  etc.,  American  Journal  of  Science,  1880. 


CONCLUSION. 


183 


swampy  ground.      This    type   of    foot    Avould    be    somewliat    like    that 
represented  in  figure  149,  below. 


Fig.  148. 


OOOOqo 
0  0  0^0° 
OP?o°1 


o  o 


FisuEE  148. — Lett  hind  \imh  ot  Ba27lanodon  discits,  Marsh;  seen  from  below ;   one-eighth  natural  size. 
Figure   140. — Right  fore  foot  of  Chelydra  serpentina,  Linnieus  ;  front  view  (after  Gegenbaur). 

F.  femur;  F'.  fibula;  «'.  intermedium ;  c.  central  bone ;/.  fibulare ;  to.  metatarsals;  K.  radiiis;  r.  radiale; 
T.  tibia;   t.  tibiale;  U.  ulna;  u.  ulnare. 

The  Roman  numerals  denote  the  ordinal  number  of  each  digit  present,  counting  from  the  inner  side 
of  the  pentadactyl  foot. 

(2.)  For  locomotion  on  dry  hard  ground,  a  stronger  foot  was 
required,  and  a  modification  would  soon  take  place,  in  the  interlocking  of 
the  metapodials  with  the  second  row  of  carpals  or  tarsals  that  supported 
them.  Examples  of  nearly  this  stage  are  seen  in  the  fore  feet  of 
Coryphodon  and  Dinoceras,  as  shown  in  figures  150  and  152,  below.  The 
fore  foot  of  the  elephant  (figure  156)  will  also  serve  to  illustrate  the  same 
stage. 

(3.)  A  still  stronger  foot  was  produced  by  the  further  interlocking 
of  both  the  first  and  second  row  of  carpals  and  tarsals,  as  well  as  the 
latter  row  with  the  metapodials  below.  This  general  type  of  foot  belongs 
to  the  Hohdactyla,  and  is  seen  also  in  some  of  the  early  Perissodactyls. 


184 


DINOCERATA. 


During  these  two  stages  of  modification,  or  at  a  later  period,  a 
reduction  in  the  number  of  digits  in  some  forms  also  took  place,  evidently 
as  a  result  of  the  same  causes.  As  progression  on  dry  land  ^Yitll  the 
plantigrade  five-toed  foot  began,  the  first  digit,  being  the  shortest  of  the 
series,  soon  left  the  ground,  and  was  gradually  lost. 


FlOURE  150. Left  fore  foot  of   Coryphodon  Tiamatus,  .Marsh,  front  view. 

FiGur.E  1 5 1  —Left  liind  foot  of  same. 

Bolh  Iisures  are  one-third  natural  size. 

Flc.  152. 


11  III 

FiGL'EE   152. — Left  fore  foot  of  Vinoceras  miruhile,  Marsh. 
F'lGUEB  153. — Left  hind  foot  of  same. 

Both  figures  are  one-fifth  natural  size. 

The  four  remaiuhig  digits,  having  to  do  the  work  of  five,  were 
strengthened  by  the  interlocking  already  mentioned,  and  also  by  coming 
neai'er  together. 

(4.)  In  the  next  change  that  occurred,  two  kinds  of  reduction 
began.  One  leading  to  the  existing  Perissodactyl  foot,  and  the  other, 
apparently  later,  resulting  in  the  Artiodactyl  type.  In  the  former,  the 
axis   of  the  foot  remained   in   ihe   middle   of  ihe   third   digit,   as    in  the 


CONCLUSION. 


185 


pentadactyl  foot.  In  the  latter,  it  shifted  to  the  outer  side  of  this  digit, 
or  between  the  third  and  fourth  toes.  An  example  of  the  former  is  seen 
in  tlie  fore  foot  of  JBrontotherium  and  Rhinoceros,  figures  158  and  160, 
below,  while  Oreodon  and  the  hippopotamus,  figures  162—165,  show  the 
latter  type. 

Fig.  155. 


Figure  154. — Left  fore  foot  of  Ilijrax  capensis,  Scbrebr. 
FiGUKE  ]  55.— Left  liind  foot  of  same. 

c  central  bone;  cT.  entocuneifurm ;  j).  pisiform;  t.  tibialo. 

Both  figures  are  natural  size. 


Fig.  156. 


Figure  156  — Left  fore  foot  o£  E'.ephas  Jndicus,  Linnseus. 
FiGURB   157. — Left  liiud  foot  of  same. 

Botll  figures  are  o:ie-ciglith  natural  size. 
24 


186 


DINOCERATA. 


The  position  of  tlie  axis  is  the  distinctive  feature  between  these  two 
types  of  feet,  and  not  the  number  of  toes,  as  the  names  usually  applied 
to  them  indicate.  In  this  respect,  the  terms  Artiodactyl  and  Perissodactyl 
are  misleading,  and  hence  the  names  Faraxonia  and  Mesaxonia  were 
proposed  by  the  author,  as  substitutes,  to  express  the  true  axial  relation. 


Figure  158. — Left  fore  foot  of  Rhinoceros  hicornis,  Linnteus. 
Figure  159. — Left  hiad  foot  of  same. 

,     Both  figures  are  one-eighth  natural  size. 


FiGUEE  160  — Right  fore  foot  of  Brontotherium  ingens.  Marsli. 
Figure  161.— Right  hind  fool,  of  same. 

Both  liijnres  are  one-si.xtli  natural  size. 


CONCLUSION. 


187 


(5.)  In  the  further  reduction  of  the  Perissodactyl  foot,  the  fifth  digit, 
being    shorter    than    the    remaining    three,    next    left   the    ground,    and 


a      17 
Figure  1C2. — Left  fore  foot  of  Eporeodon  socialis,  Marsh. 
Figure  ]  63. — Left  hind  foot  of  same. 

Both  figures  are  one-third  natural  size. 


M         17  n        IV 

Figure  164. — Left  fore  foot  of:  lUppupUamus  amphibius,  LinujRu.s, 
Figure  1G5. — Left  hind  foot  of  same. 

Both  figures  are  one-elghlh  natural  size. 

gradually  disappeared.  Of  the  three  remaining  toes,  the  middle,  or  axial, 
one  was  the  longest,  and  retaining  its  supremacy,  as  greater  strength  and 
speed  were  required,  finally  assumed  tbe  chief  support  of  the  foot,  while 


188 


DINOCERATA. 


the  outei'  dig-its  left  the  ground,  ceased  to  be  of  use,  and  were  lost, 
except  as  splint  bones.  The  foot  of  the  existing  horse  (figures  166  and 
167)  shows  the  best  example  of  this  reduction  in  the  Perissodactyls,  as 
it  is  the  most  specialized  known  in  the  Ungulates. 

Fig.  16T. 


iir  M  M  N  m  N 

Figure  1 66. — Left  fore  foot  of  horse  {Equus  caballus,  Linnajus). 
Figure  167. — Left  hind  foot  of  same. 

Both  figures  are  one-eighth  natural  size. 
Figure  168. — Left  fore  foot  of  goat  {Capra  Idrcus,  Linnaeus). 
FiGUBE   1 69. — Left  hind  foot  of  same. 

Both  figures  are  one- fifth  natural  size. 

(6.)  In  the  Artiodactyl  foot,  the  reduction  resulted  in  the  gradual 
diminution  of  the  two  outer  of  the  four  i-emaining  toes,  the  tliii'd  and 
fourth  doing  all  the  work,  and  thus  increasing  in  size  and  power.  The 
fifth  digit,  for  the  same  i-easons  as  in  the  Perissodactyl  foot,  first  left  the 
o-round,  and  became  smaller.  Next,  the  second  soon  followed,  and  these 
two  gradually  ceased  to  be  functional,  or  were  lost  entirely,  as  in  some 
of  the  Artiodactyls  of  to-day.  The  feet  of  the  goat,  figures  168  and  169, 
above,  show  this  extreme  reduction. 

As  the  author  has  shown  elsewhere,  these  reductions  of  the  feet,  and 
of  the  entire  limbs,  led  to  greater  strength  and  speed,  as  the  motion, 
before  irregular,  gradually  came  to  act  in  a  single  plane. 


CONCLUSION.  189 

The  limb  of  tlie  modern  race-horse  is  a  nearly  perfect  piece  of 
machinery,  especially  adapted  to  great  speed  on  dry,  level,  ground.  The 
limb  of  an  antelope,  or  deer,  is  likewise  well  fitted  for  rapid  motion  on 
a  plain,  but  the  foot  itself  is  adapted  to  rough  mountain  work,  as  well, 
and  it  is  to  this  advantage,  in  part,  that  the  Artiodactyls  owe  their  present 
supremacy. 

The  plantigrade,  pentadactyl,  foot  of  the  primitive  Ungulate,  and 
even  the  Perissodactyl  foot  that  succeeded  it,  both  belong  to  the  past 
humid  period  of  the  world's  history.  As  the  surface  of  the  earth  slowly 
dried  up,  in  the  gradual  desiccation  still  in  progress,  new  types  of  feet 
became  a  necessity,  and  the  liorse,  antelope,  and  camel,  were  gradually 
developed,  to  meet  the  altered  conditions. 

The  Proboscidians  and  Perissodactyls  now  living,  except  the  horse, 
are  doomed  to  early  extinction,  but  the  Artiodactyls,  with  their  greater 
power  of  adaptation,  will  replace  them,  and  perhaps  develop  new  forms. 

The  genealogy  of  the  special  Ungulate  lines  which  ended  in  the 
hors.e,  tapir,  and  rhinoceros,  of  the  Perissodactyls,  and  of  the  pig,  camel, 
and  deer,  among  the  Artiodactyls,  has  already  been  marked  out  by  the 
author  elsewhere,^  and  need  not  here  be  repeated,  esjjecially  as  the 
subject  will  be  fully  discussed  in  a  future  volume. 

Extinction  of  Laege  Mammals. 

During  the  Mesozoic  period,  all  the  mammals  appear  to  have  been 
small,  and  it  is  not  probable  that  any  of  large  size  existed,  as  reptilian 
life  then  reigned  supreme.  With  the  dawn  of  the  Tertiary,  a  new  era 
began,  and  mammalian  life  first  found  the  conditions  for  its  full  and 
rapid  development. 

In  the  lower  Eocene,  the  largest  land  mammal  was  Coryphodon,  more 
than  the  equal,  in  size  and  power,  of  any  of  the  reptiles  of  that  time. 
Dinoceras  and  its  allies,  in  the  middle  Eocene,  were  much  larger,  and  were 

'  Introduction   atlcl   Succession  of  Vertebrate  Life    in    America,   1877.     See   also 
New  Equine  Mammals,  etc.,  1874,  and  Polydaotyle  Horses  Recent  and  Extinct,  1879. 


190  DINOCERATA. 

clearly  the  monarclis  of  the  region  in  which  they  lived.  In  the  upper 
Eocene,  Biplacodon,  about  the  size  of  the  rhinoceros,  was  the  largest 
mammal,  but  each  of  these  three  died  out  in  the  period  in  which  it 
flourished. 

At  the  base  of  the  Miocene,  the  huge  Brontotheridce,  nearly  as  large 
as  the  elephant,  suddenly  appear  in  great  numbers.  They  remained  for 
a  short  time  the  dominant  land  animals,  and  then  became  extinct. 

The  Proboscidians  were  the  giants  of  the  Pliocene,  and  hold  the 
supremacy  in  size  to-day,  but  are  evidently  a  declining  race,  and  must 
soon  disappear. 

The  cause  of  the  successive  disap23earance  of  each  group  of  these 
large  Tertiary  mammals  is  not  difl&cult  to  find.  The  small  brain,  highly 
specialized  characters,  and  huge  bulk,  rendered  them  incapable  of 
adapting  themselves  to  new  conditions,  and  a  change  of  surroundings 
brought  extinction.  Smaller  mammals,  with  larger  brains,  and  more  plastic 
structure,  readily  adapt  themselves  to  their  environment,  and  survive,  or 
even  send  off  new  and  vigorous  lines. 

The  Dinocerata,  with  their  very  diminutive  brain,  fixed  characters,  and 
massive  frames,  flourished  as  long  as  the  conditions  were  especially 
favorable,  but,  witli  the  first  geological  change,  they  perished,  and  left 
no  descendants. 

Classification  of  Dinocerata. 

The  relations  of  the  Dinocerata  to  other  orders  of  mammals  have  now 
been  fully  considered  in  the  preceding  pages,  and  the  main  conclusions 
reached  are  given  on  pages  173  and  177.  The  generic  sub-divisions  of 
this  group  do  not  appear  widely  separated  from  each  other,  although  at 
least  three  types,  from  successive  geological  horizons,  can  be  distinguished. 
The  species  are  numerous,  and  well  marked,  and  there  is  strong  evidence 
that  many,  if  not  all  of  them  are  from  separate  horizons.  The  differences 
due  to  age  and  sex  are  also  manifest,  and  have  been  duly  considered  in 
estimatino^  distinctive  characters. 


CONCLUSION. 


191 


The  Binocerata  now  known  may  be  placed  in  three  genera :  JDinoceras, 
Tinoceras,  and  Uintatherium.  These  may  be  separated  by  characters  of 
the  skull,  vertebrae,  and  feet.  There  are  also  indications  of  several 
intermediate  forms,  which  may,  perhaps,  be  found  to  represent  sub-genera, 
when  additional  specimens  in  good  preservation  are  secured  for  comparison. 
Twenty-nine  species  may  be  distinguished,  mainly  by  the  skull  alone, 
which,  at  present,  offers  the  best  distinctive  characters. 

Sub-order  DINOCERATA,  Marsh. 
Family  Tinoceratid^,  Marsh. 


Uintatherium,  Leidy. 

Teeth,  thirty-six. 
Lower  premolars^  four. 
Base  of  canine  tusk, 

nearly  vertical. 
Parietal    protuberance 

above   post-glenoid 

process. 
Cervical  vertebrae  of 

moderate  length. 
Lunar  articulating  with 

trapezoid  ? 


Binoceras,  Marsh. 

Teeth,  thirty-four. 
Lower  premolars,  three. 
Base  of  canine  tusk, 

nearly  vertical. 
Parietal  protuberance 

above  post-glenoid 

process. 
Cervical  vertebrae  less 

elongate. 
Lunar  articulating  with 

trapezoid. 


Tinoceras,  Marsh. 

Teeth,  thirty-four. 
Lower  premolars,  three. 
Base  of  canine  tusk, 

horizontal. 
Parietal  protuberance 

behind  post-glenoid 

process. 
Cervical  vertebrae  short. 

Lunar    not    articulating 
with  trapezoid. 


These  three  genera  clearly  represent  three  stages  of  development  of 
the  Binocerata,  and  these  stages  correspond  to  the  successive  horizons  of 
the  middle  Eocene  in  which  the  remains  of  these  animals  were  entombed. 
Uintatherium,  the  most  generalized  type,  is  found  at  the  lowest  level ; 
Binoceras  is  from  a  somewhat  higher  stratum ;  and  Tinoceras,  the  most 
specialized  of  all,  occurs  in  the  latest  deposits. 

In  the  S3aiopsis  which  follows  this  chapter,  a  systematic  list  of  all  the 
species  of  the  Binocerata  is  given  in  detail.  In  connection  with  the 
preceding  pages,  and  the  Plates  at  the  end  of  the  volume,  this  will  place 
before  the  reader  everything  of  importance  now  known  in  regard  to  the 
Binocerata. 


APPEI^DIX. 


SYNOPSIS    OF    DINOCERATA. 

The  present  synopsis  contains  a  list  of  all  the  known  species  of  the 
Dinocerata,  and  at  least  one  characteristic  figure  of  each  species  not 
elsewhere  illustrated  in  this  volume.  Full  references,  also,  are  given  to 
all  the  important  literature.  The  complete  titles  of  the  works  cited  will 
be  found  in  the  Bibliography,  which  follows  this  synopsis.  A  brief 
history  of  the  discovery  of  each  specimen  of  importance,  with  the  locality, 
geological  horizon,  collector,  date,  the  nature  of  the  remains,  and  where 
now  preserved,  is  likewise  j)laced  on  record  under  each  species,  as  an 
essential  part  of  a  Monograph  of  the  group. 

The  dates  of  publication  of  the  various  papers  on  the  Dinocerata  have 
been  carefully  reexamined,  and  those  here  given  are  substantiated  by 
conclusive  evidence.  The  names  adopted  for  genera  and  species  are 
based  on  priority  alone,  except  in  the  cases  of  those  already  used.  For 
the  higher  groups,  the  new  names  proposed  are  to  replace  those  previously 
applied,  or  to  gain  appropriate  terms  for  nomenclature.  Amblydactyla  has 
thus  been  substituted  for  Amhlypoda,  and  CorypJiodontia,  for  Pantodonta, 
the  names  replaced  being  both  essentially  pre-occupied.  The  last  term, 
moreover',  has  no  significance  when  applied  to  the  group  of  which 
Coryphodon  is  the  original  and  characteristic  type.  The  names  Protungidata, 
Holodactyla,  and  Glinodactyla,  express,  respectively,  a  jjrominent  feature  of 
the  groups  they  represent,  and  hence  have  been  introduced  in  the 
preceding  chapter. 

25  193 


194  DINOCERATA. 

DINOCERAS;    Marsh,    1872. 

Diiioceras  luiraMle,  Marsh. 
(Plates  I-VIII,  XX-XLII,  XLIV-LV.) 

Woodcuts:  3,  p.  13;  7,  p.  15;  13,  p.  19;  26,  p.  26;  34,  35,  p.  31;  39,  40,  p.  38;  43,  44,  45, 

p.  42;  63,  p.  61;   89,  90,  p.  76;   91,  92,  p.  77;  95,  96,  p.  80;  99,  100,  p.  82;  106,  107, 

p.  91;   108,  109,  p.  94;   111,  p.  98;   113,  p.  103;    114,  p.  105;   118,  p.  108;   119, 

120,  p.  112;   121,  122,  p.  115;    123,  p.  119;   129,  130,  131,  132,  p.  131; 

133,  p.  134;   137,  138,  p.  141;  143,  144,  p.  152;  145,  146,  p.  154; 

152,  153,  p.  184. 

Marsh,  American  Journal  of  Science  and  Arts  (3),  Vol.  IV,  p.  344,  October,  1872;  Vol. 
V,  p.  119,  Plales  I  and  II,  February,  18V3;   Vol.  XI,  p.  164,  Plates  II-IV,  February, 
1876;  Vol.  XXII,  pp.  31,  32,  Plate  II,  July,  1881. 
American  Naturalist,  Vol.  VII,  p.  148,  Plates  I  and  IT,  March,  1873. 
Proceedings  of  the  American  Philosophical  Society,  Vol.  XII,  p.  579;  1872;  Vol.  XIII, 

p.  256,  1873. 
Fifth  Annual  Report  of  the  U.  S.  Geological  Survey,  (figures  from  present  volume, 
viz:)  fig.  38,  p.  256;    39,  p.  257;    40,  p.  258;    44,  p.  260;    50,  p.  263;    61,  p.   268; 
69,  70,  p.  272;    76,  77,  p.  275;    80,  81,  82,  p.  278;     100,  p.  289;     116,  117,  p.  295; 
120-123,  p.  296;   134,  135,  p.  301;   136,  p.  302,   1884. 
Garrod,  Journal  of  Anatomy  and  Physiology,  Vol.  VII,  pp.  267,  268,  June,  1873. 
The  same.  Complete  Writings,  i^p.  121,  122,  1881. 
Nature,  Vol.  VII  (skull  figured),  p.  366,  March  13,  1873. 
Gaudry,  Les  Enchainements  du  Monde  Animal,  p.  74,  fig.  86,  1878. 
Nicholson,  Manual  of  Palseontology,  Vol.  II,  pp.  870-373,  figs.  656,  657,  1879. 
Dana,  Manual  of  Geology,  3d  ed.,  Plate  VII,  figs.  1-4  (from  pi-esent  volume),  1880. 
LeConte,  Elements  of  Geology,  pp.  525,  526,  figs.  845,  845rt  (from  present  volume),  1882. 
Flower,  Encyclopedia  Britannica,  Vol.  XV,  p.  426,  fig. '105,  1883. 

Cope  (Uintatherium  mirabile). — Hayden's  Report  U.  S.  Geological  Survey  of 
the  Territories  for  1872,  pp.  581,  584,  1873. 
Proceedings  of  the  Philadelphia  Academy  of  Natural  Sciences,  Vol.  XXV,  p.  102,  1873. 
Proceedings  of  the  American  Philosophical  Society,  Vol.  XIII,  pp.  61,  65,  1873. ' 
Leidy  (Uintatherium    mirabile). — Extinct  Vertebrate  Fauna,  pp.  97,  108,  332, 

333,  1873. 
Osborn  (Uintatherium  mirabile). — Memoir  upon  Loxolophodon  and  Uintatherium, 
pp.  24,  25,  1881. 

The  type  specimen  (number  1036)  of  this  species  was  obtained  in 
1872  and  1873,  by  Messrs.  B.  U.  Smith,  J.  W.  Chew,  and  the  author,  from 
Big  Bone  Buttes,  about  twenty  miles  east-southeast  of  Fort  Bridger,  and 
twenty-five  miles  west  of  Green  River,  Wyoming-. 

'  /Isivoi,  terrible,  and  Hspai,  a  horn. 


SYNOPSIS.  -^<jg 

cervic^!!''. jr'"f''  '°"T'  °^.'^  '^""'  ^°™Pl<^t«  <^^«ept  tlie  lower  iaws 
ceivca   and  lumbar  vertebra.,  ribs,  pelvis,  limb  bones,  itc  ^        ' 

Other  specimens  here  refeiTcA:!  to  this  species  are  Ls  follows- 

Kivei    Wyoming,  and  consisting  of  bones  of  the  fore  le-  and  foot 
Number  1199,   collected  by  Mr    F    S   Wicks   in  1^7 R   .o      tt 

^^1f-,-Si]j-/i-^^^ 

Xll  Wr^^^^  ^^  ^^-^^^^  ^^^-'   ^^^---^^'   --'^t-^.-   pHncljaii/^^oJ- 

west  of"Sen;;i'Forr""i'^  ^^V^"  ^;  ^"•-^^^•'  ^^  ^^TS,  from  the  Divide 
west  ot  Memy  sjork,  and  consisting  of  a  radius,  ulna,  femur  etc 

187S   n™    ^  '''n'  'f'T^  ^^'  ^^^-  J-  W-  CI-w  and  m"  B.'  D  Smith   in 
1873   near  Sage  Creek,  about  fifteen  miles  southeast  of  Fort  Brid"m  ^rd 

oflJfe^refo       ""*  ^'^^"^^^  ^^^^^^  ^^--"^'  --^  consistinrof  bc^^ 

Number  1210    obt.^ined  by  Mr.  J.   W.   Chew,   November    1874    in 

^l2C\^T'''TfrrT^  '^"^^"'  P^^^'  *^bia,  feet  bonel^'etc 
_         JNumbei   1211,  collected  by  Messrs.  H.  G.  Chenev  and   H    A    nX. 

Number    1212,    obtained    by   Messrs     S     Smith    ind    T     W     ni 

about  eighteen  miles  west  of  Green  River,  Wyoming,  and  con  istin^' of  a 
scapula,  portions  ol  the  pelvis   etc  i^onsibnng  ot  a 

octobt-l875'fbo;t'?o'"*''i  '^;  i'^"^?-  ^-  ^™^*  ^-^  ^-  p---".  in 

uctot)eiia75   about  four  miles  below  Lone  Tree,  on  Henry's  Fork   knd 

mrTof.  Ik. l"t''  "'■''  '^S''T  ^^^"^■'  ^y'^-"^-  -^d  consistfngof  a  i^e 
part  of  a  skeleton,  especially  bones  of  the  feet  and  leo-g  "  ^ 

Number  1225,  collected  by  Mr.  J.  W.  Chew,  nea?  Henry's  Fork   about 
Number  1226,  collected  in  1873,  by  Messrs    S    Smith    T  W  n\. 

Number  1230,  collected  by  Mr.  E.  S.  Lane,  in  August   1873   on  the 
Dzy:de  west  of  Henry's  Fork,  Wyoming,  and  coi'.sisting  ^carpd  bones 


196  DINOCERATA. 

Number  1232,  collected  by  Mr.  J.  W.  Chew,  in  1874,  in  Wyoming, 
consisting  of  parts  of  a  pelvis,  and  various  limb  bones. 

Number  1234,  collected  by  Mr.  L.  Lamotte,  at  Camp  Springs, 
Wyoming,  in  1873,  consisting  of  limb  bones,  caudal  vertebrae,  etc. 

Number  1245,  collected  in  1872,  by  Messrs.  B.  D.  Smith  and  J.  W. 
Chew,  at  Big  Bone  Buttes,  Wyoming,  and  consisting  of  a  humei'us,  etc. 

Number  1247,  collected  in  November,  1873,  by  Messrs.  S.  Smith  and 
J.  W.  Chew,  at  Tule  Springs,  near  Sage  Creek,_  Wyoming,  and  consisting 
of  tarsal  bones,  etc. 

Number  1248,  collected  by  Mr.  B.  D.  Smith,  in  1871,  at  Henry's  Fork, 
Wyoming,  and  consisting  of  axis,  femur,  tibia,  etc. 

Number  1251,  collected  by  Mr.  J.  Heisey,  May,  1876,  eight  miles 
south  of  Dug  Springs,  near  Haystack  Mountain,  about  sixty-five  miles 
east  of  Green  River,  and  twenty-five  miles  south  of  the  Union  Pacific 
railroad,  Wyoming,  and  consisting  of  vertebrae,  etc. 

Number  1252,  collected  by  Mr.  S.  Smith,  in  February,  1875,  north  of 
Leavitt's  Ranch  on  Henry's  Fork  about  twenty  miles  west  of  Green  River, 
Wyoming,  consisting  of  parts  of  the  skull,  a  tibia,  fibula,  etc. 

Number  1255,  collected  in  June,  1874,  by  Mr.  L.  Lamotte,  at  Big 
Bone  Buttes,  and  consisting  of  part  of  the  lower  jaws,  showing  milk 
incisors  in  position,  cervical  and  dorsal  vertebrae,  ribs,  and  limb  bones,  etc. 

Number  1490,  collected  by  Mr.  L.  Lamotte,  in  Wyoming,  and 
consisting  of  incisor  teeth. 

Number  1514,  collected  by  Mr.  J.  Heisey,  May,  1876,  eight  miles  south 
of  Dug  Springs,  Wyoming,  and  consisting  of  lower  jaws  with  molars. 

Number  1520,  collected  by  Dr.  J.  V.  A.  Carter,  in  Wyoming, 
consisting-  of  fragments  of  a  skull,  carpal  bones,  vertebrae,  etc. 

Number  1528,  collected  by  Mr.  J.  W.  Chew,  in  1875,  near  Henry's 
Fork,  Wyoming,  consisting  mostly  of  tarsal  bones. 

Number  1529,  collected  in  Wyoming,  by  an  Lidian,  called  Shoshone 
John,  and  consisting  of  a  considerable  number  of  bones  from  several 
difi^erent  skeletons. 

Number  1548,  collected  by  Messrs.  S.  Smith  and  J.  W.  Chew,  in 
November,  1873,  near  Sage  Creek,  Wyoming,  consisting  of  a  parietal 
horn-core,  leg  bones,  etc. 

The  geological  horizon  of  all  these  specimens  is  in  the  Dinoceras,  or 
Bridger,  beds  of  the  Middle  Eocene,  as  shown  in  the  section  on  page  7. 

•  The  remains  of  the  specimens  here  described  are  preserved  in  the 
Museum  of  Yale  College. 


SYNOPSIS.  197 

Dinocei'cas  agreste,  Marsh,  n.  s. 

Woodcut:   15,  p.  19. 

In  this  species,  the  nasals  are  seijarated  in  front  by  a  distinct  suture, 
extending  back  beyond  the  anterior  jjrojection  of  the  preinaxillaiy  bone. 
They  taper  to  a  bhint  conical  point,  which  is  much  roughened,  but 
presents  no  certain  evidence  of  the  attachment  of  prenasals. 

The  diastema  behind,  the  upper  canine  is  nearly  straight,  and  of 
moderate  length  (about  7  cm.),  and,  in  this  region,  the  palate  is  strongly 
vaulted.     The  palato-maxillary  foramen  is  opposite  the  first  premolar. 

The  posterior  end  of  the  malar  bone  was  received  into  a  shallow  jjit, 
in  front  of  the  glenoid  cavity  of  the  squamosal. 

The  occiput  (figure  15,  page  19)  has  the  upper  angles  well  rounded, 
and  presents  a  median  tubercle  in  the  line  of  the  vertical  ridge.  The 
foramen  magnum  is  broad,  and  rises  somewhat  above  the  level  of  the 
condyles. 

The  type  specimen  (number  1221)  of  this  species  was  discovered  in 
1873,  by  Mr.  L.  Lamotte,  near  Spanish  John's  Meadow,  about  thirty  miles 
east-southeast  of  Fort  Bridger,  and  fifteen  miles  west  of  Green  River, 
Wyoming 

This  specimen  consists  of  a  skull,  scapula,  ribs,  etc. 

The  geological  horizon  of  this  species  is  in  the  Dinoceras  beds  of  the 
Middle  Eocene. 

The  known  remains  of  this  species  are  preserved  in  the  Yale  College 
Museum. 

Dinoceras  cimeiim,  Marsh,  n.  s. 

Woodcuts  93,  94,  p.  77  ;  170,  171,  below. 

Fig.  170. 

b. 


Figure  170 — Nasals  c\i  Dinoceras  cuneum.  Marsh  (No.  1207). 
a.  side  view;  6.  top  view;  c.  front  view. 

One-fil!tli  natural  size. 


The  skull  in   this  species  tapers  in  front,  but,  in  the  type-specimen 
(number   1042),   the  nasal  protuberances  are   not  well  preserved.     The 


198  DINOCERATA. 

maxillary  protuberances  are  well  developed,  divergent,  and  connected  by 
a  moderate  ridge.  The  top  of  the  skull  behind  this  is  flattened,  and 
separated  from  the  lateral  surface  by  a  more  or  less  prominent  ridge, 
rising  well  on  the  front  surface  of  the  elevated  parietal  processes.  These 
processes  are  over  the  post-glenoid  processes.  They  are  high,  and, 
toward  the  apex,  flattened  antero-posteriorly,  while  they  expand  in 
transverse  diameter.  The  ridge  connecting  them  across  the  surface  of  the 
skull  is  present,  but  not  elevated. 

The  foramen  magnum  is  slightly  higher  than  the  occipital  condyles. 
The  palate  is  excavated  in  the  region  of  the  diastema. 


Figure  171. — Skull  of  Dinoceras  cuneum,  Marsh  (No.  1042);  seen  from  above. 

One-eighth  natural  size. 

Another  specimen  (number  1207,  figure  170)  has  the  siiout  very 
tapering  in  front,  and  the  nasal  protuberances  small,  though  rather 
prominent.  The  median  suture  is  entirely  obliterated,  and  the  prenasals, 
if  present,  are  thoroughly  co-ossified  with  each  other,  and  with  the  nasa-l 
bones. 

The  maxillary  prominences  are  rounded,  and  not  very  divergent. 
The  parietal  protuberances  are  connected  by  a  transverse  ridge.  The 
zygomatic  process  of  the  squamosal  is  not  excavated  for  the  posterior 
end  of  the  malar. 

The  type  specimen  (number  1042)  of  this  species  was  secured  in  May, 
1875,  by  Messrs.  S.  Smith  and  J.  Heisey,  near  Haystack  Mountain, 
about  sixty-five  miles  east  of  Green  River,  Wyoming. 

The  specimen  consists  of  a  skull,  with  a  nearly  complete  series  of 
dorso-lumbar  vertebrae,  sacrum,  pelvis,  etc. 

The  second  specimen  (number  1207),  consisting  of  portions  of  the 
skull  and  vertebrae,  was  found  by  J.  W.  Chew  and  the  author,  in  1873, 
near  Big  Bone  Buttes,  Wyoming. 

The  geological  horizon  is  in  the  Bridger  beds  of  the  Middle  Eocene. 

The  only  known  specimens  are  in  the  Yale  Museum. 


SYNOPSIS.  199 

Dinoceras  distans,  Marsh. 

Woodcuts:  4,  p.  13;  8,  p.  15;  10,  p.  16;  31,  p.  29. 

Marsh,  Fifth  Annual  Report  U.  S.  Geological  Survey  (figures  from  the  present  volume, 
viz  :)  fig.  41,  p.  258;  45,  p.  260;  06,  p.  270,  1884. 

The  skull  in  the  type  specimen  of  this  species  (number  1235)  has 
nearly  the  same  general  sliape  as  in  the  type  of"  Dinoceras  mirabile,  but  is 
somewliat  more  robust,  though  pertaining  to  a  young  animal,  as  shown  by 
the  generally  open  sutures.  The  nasals  taper  in  front,  and  bear  a  pair  of 
low  rounded  oblique  tubercles,  much  as  in  number  1036.  They  are 
terminated,  as  in  that  specimen,  by  flattened,  nearly  vertical,  and  deeply 
pitted,  sutural  surfaces,  from  which  the  prenasals  have  fallen  away. 

The  maxillary  elevations  are  stout  and  conical,  and  are  connected 
across  the  median  line  of  the  skull  by  an  elevated  ridge.  The  naso- 
maxillary suture  curves  inward  between  the  maxillary  protuberances,  and 
is  strongly  mai-ked  on  their  inner  surfaces. 

Behind  the  maxillary  protuberances,  the  top  of  the  skull  is  flattened, 
and  presents  two  low  oblicpe  ridges,  converging  behind,  along  the  lines  of 
the  Iron  to-nasal  sutures.  At  the  sides,  the  superior  surface  is  separated 
from  the  lateral  by  a  ridge,  which  rises  nearly  to  the  top  of  the  parietal 
protuberances.  These  are  well  developed,  triangular  in  section,  and 
directed  upward  and  outward,  and  are  situated  above  the  post-glenoid 
processes.  The  foramen  magnum  is  below  the  upper  margin  of  the 
occipital  condyles. 

In  the  type  specimen,  the  post-glenoid  process  is  robust.  The 
zygomatic  process  of  the  squamosal  is  deeply  excavated  in  front  of  the 
glenoid  cavity,  for  the  posterior  end  of  the  malar  bone,  which  is 
peculiarly  blunt,  and  rounded  behind.  The  jmlato-maxillary  foramen  is 
rounded,  and  placed  opposite  the  posterior  half  of  the  first  jjremolar. 

The  cavity  for  the  brain  is  exposed  in  this  specimen,  and  shows  a 
nasal  septum  just  in  front  of  the  anterior  constriction.  The  short  olfactory 
lobes  were  bounded  in  front  by  thin  cribriform  plates. 

The  young  specimen  (number  1601)  agrees  with  the  type  (number 
1235)  in  the  general  shape  of  the  skull,  in  the  form  of  the  maxillary 
protuberances  and  connecting  ridge,  in  the  shape,  and  position  of  the 
parietal  protuberances,  and  in  the  position  of  the  palato-maxillary  foramen. 
Also  in  the  deep  excavation  for  the  end  of  the  malar  bone.  The  known 
differences  may  be  attributed  to  age. 

Thet^'pe  of  this  species  (number  1235)  was  collected  by  Mr.  S.  Smith, 
in  1874,  near  Lone  Tree,  on  Henry's  Fork,  Wyoming. 

The  second  specimen  (number  1601)  was  found  by  Mr.  Smith  in  1882, 
near  Haystack  Mountain,  Wyoming. 

The  geological  horizon  of  this  species  is  in  the  Dinoceras  beds. 

The  type  specimen  of  this  species  is  preserved  in  the  Yale  Museum. 


200 


DINOCERATA. 


Woodcuts 


Dinoceras  laticeps,  Marsh. 

(Plates  X-XIV,  XLIII.)    ' 

:    14,  p.  19;    22,  p.  25;  27,  p.  26;  33,  p.  30;    47,  p.  43;    50 
and  112,  p.  103;   136,  p.  138;   139,  140,  p.  149. 


I,  p.  44;    57,  58,  p.  54; 


Marsh,  American  Journal  of  Science  and  Arts  (3),  Vol.  VI,  p.  301,  October,  1873;   Vol. 

XI,  p.  164,  Plate  V,  February,  1876. 
Osborn  and  Speir  (Uintatherium  laticeps). — American  Journal  of  Science  and 

Arts  (3),  Vol.  XVII,  pp.  3G4,  305,  307,  April,  1879. 

The  type  of  this  species  possesses  the  main  characters  of  Dinoceras, 
but,  in  the  premaxillaries,  palate,  and  brain-cavity,  shows  an  approach 
to  Tinoceras,  especially  Tinoceras  pugnax.  It  apparently  represents  a 
sub-genus  of  Dinoceras,  which  va&j  be  called  Paroceras. 

The  type  specimen  of  this  species  (number  1039)  was  obtained  in 
August,  1873,  by  Mr.  L.  Lamotte  and  the  author,  near  Spanish  John's 
Meadow,  Wyoming. 

This  specimen  consists  of  a  skull,  lower  jaws,  vertebra;,  etc. 

A  second  specimen,  a  female  (number  1202),  consisting  of  a  skull  and 
other  parts  of  the  skeleton,  was  found  by  the  author,  in  August,  1873,  near 
Henry's  Fork,  about  thirty  miles  west  of  Green  River,  Wyoming. 
Additional  specimens  are  numbers  1197,  1222,  1239,  and  1264. 

The  geological  horizon  of  this  species  is  in  the  Dinoceras  beds  of  the 
Middle  Eocene. 

The  known  remains  of  this  species  are  in  Yale  College  Museum. 


Dinoceras  lucare,  Marsh. 

(Plate  IX.) 

Woodcuts:  46,  p.  43;  103,  104,  105,  p.  84;  110,  p.  98 


172.  173,  below. 


Figure  172. — Nasals  of  Dinoceras  lucare,  Marsh  (No.  ]038). 
a.  side  view ;  b.  top  view  ;  c.  front  view. 

One-fif  Ih  natural  size. 


SYNOPSIS. 


201 


FisuEE   173. — N asa,\s  ot  Dinoceras  liicare,  Marsh  (N'o.  1568). 
a.  side  view;  b.  top  view;  c.  front  view. 

One-flftli  natural  size. 

Afarsh,  American  Journal  of  Science  and  Arts  (3),  Vol.  V,  p.  408,  May,  187.3. 

Fifth  Annual  Report  of  the  U.  S.  Geol.  Survey,  (figures  from  the  present  volume  viz-) 
fig.  83,  p.  279;    124,  125,  p.  296,  1884.  ' 

Leidy  (Uintatherium).— Extinct  Vertebrate  Fauna,  p.  .334,  1873. 

The  type  specimen  of  this  species  (number  1038)  was  obtained  by 
IVressrs.  B.  D  Smith,  J.  W.  Chew  and  the  author,  two  miles  east  of  Big- 
Hone  Buttes,  Wyoming-,  September,  1872,  and  September,  1873. 

This  specimen  consists  of  a  skull,  and  numerous  parts  of  the  skeleton. 

The  geological  horizon  of  this  species  is  in  the  Bridger  Beds  of  the 
Middle  Eocene. 

The  remains  of  this  specimen  are  preserved  in  Yale  College  Museum. 


Dinoceras  reflexiim,  Marsh,  n.  s. 

Woodcut  :   174,  below. 


Figure  174. — Nasals  at  D^ioceras  reflexum,  Marsh  (No.  1229). 
a.  side  view ;  b.  top  view  ;  c.  front  view. 

One-fifth  natural  size. 

In  the  type  of  this  species  (number  1229),  the  nasal  protuberances  are 
small,  but  prominent,  and  are  directed  strongly  upward.  The  nasal  bones 
are  completely  united  to  the  end,  but  are  there  terminated  by  sutural 
surfaces,  looking  nearly  downward,  and  indicating  the  position  of  the 
prenasal  bones,  Avliich  have  fallen  away.  The  suture  between  tlie  nasal 
and  the  premaxillary  is  evident,  behind  and  below  the  nasal  protuberance. 
26 


202 


DINOCERATA. 


The  post-glenoid  process  is  large  and  strong,  and  the  zygomatic 
process  of  the  squamosal  presents  a  pit  for  the  end  of  the  malar  bone  jnst 
in  front  of  the  glenoid  cavity.  The  occipital  crest  shows  a  median  keel 
on  its  posterior  surface. 

A  cervical  centrum,  from  which  tlie  epiphyses  have  nearly  separated, 
shows  that  these  vertebme  were  proportionally  shorter  than  in  number 
1255.  The  vertical  diameter  is  to  the  longitudinal  as  1  to  .55,  while  in 
number  1255  these  dimensions  are  about  as  1  to  .6. 

A  pyramidal  bone,  accompanying  these  specimens,  has  the  face  for 
the  fifth  metacarpal  confluent  with  that  for  the  unciform,  as  in  figures  117 
and  118,  page  108,  instead  of  distinct,  as  on  Plate  XXXII,  figure  6. 

The  specimen  (number  1229)  upon  which  the  species  is  based  was 
collected  in  October,  1873,  by  Messrs.  J.  W.  Chew  and  S.  Smith,  at  Tule 
Springs,  Wyoming. 

This  specimen  consists  of  fragments  of  the  skull,  limb  bones,  etc. 

The  geological  horizon  of  this  species  is  in  the  Bridger  beds  of  the 
Middle  Eocene. 

The  known  remains  are  preserved  in  Yale  College  Museum. 


TINOCERAS,"  Marsh,  1872. 

Tiiioceras  aiiceps,  Marsh. 

Woodcuts:  97,  98,  p.  80;  lYS,  176,  177,  below. 


Figure  175. — Nasals  of  Tinoceras  anceps,  Marsh  (No.  126R). 
a.  side  view;  h.  top  view;  c.  front  view. 

One-fiflh  natural  size. 

Marsh  (Titanotherium  ?  anceps.) — American  Journal  of  Science  and  Arts  (3), 
Vol.  II,  p.  35,  July,  1871. 

(Mastodon  anceps.) — American  Journal  of  Science  and  Arts,  Vol.  IV,  p.  123, 
note,  August,  1872. 

(Tinoceras  anceps.) — American  Journal  of  Science  and  Arts  (3),  Vol.  IV 
p.  322,  October,  1872.  (The  name  Tmoeefas  was  published  in  advance,  August  19. 
1872,  see  Bibliography.)  Vol.  IV,  p.  323,  October,  1872;  Vol.  IV,  p.  504,  Decem- 
ber, 1872;  Vol.  V,  pp.  117,  122,  February,  1873;  Vol.  V,  p.  296,  April,  1873. 


TivcD,  to  tear,  and  utpai,  horn. 


SYNOPSIS. 


203 


FlGTTTiK  nc. — Left  parietal  protuberance  of  Tinoceras  anceps.  Marsh  (Xo.  1030); 
FiGUKE  177. — The  same  specimen;  front  view. 
a.  anterior  crest ;  5.  posterior  crest. 

Botli  figures  are  one-half  natural  size. 


Marsh,  American  Naturalist,  Vol.  VII,  p.  52,  January,  18Y3;  pp.  147,  152,  March,  18Y3; 

p.  218,  April,  1873;  Vol.  VII,  Appendix,  p.  viii,  June,  1873. 
Proceedins;s  of  the  American   Philosophical  Society,  Vol.  XII,  p.  578,  for  1872,  1873; 

Vol.  XIII,  p.  256,  1873. 
Cojje    (Uintatherium    aneeps.) — Proceedings    of    the   American    Philosophical 

Society,  Vol.  XIII,  p.  61,  1873. 

The  type  specimen  of  this  species  was  of  small  size,  and  evidently 
a  female.  The  occiput  is  elevated,  and  has  a  median  vertical  I'idge. 
The  lateral  crests  extend  from  the  front  nearly  to  the  summit  of  the 
parietal  protuberances.  The  latter  are  connected  by  a  strong  ridge  passing 
directly  over  the  brain-cavity.  The  post-glenoid  processes  are  triangular 
in  horizontal  section,  with  the  apex  outward, 

A  second  specimen  (number  1266)  has  the  nasal  protuberances  of 
moderate  size,  and  resembling  those  of  Tinoeeras  grande.  The  prenasal 
bones  are  firmly  co-ossified  with  the  nasals. 

The  type  specimen  (number  1030)  was  discovered  by  Lieut.  W.  N. 
Wann,  in  September,  1870,  on  the  Divide  near  Sage  Creek,  fifteen  miles 
southeast  of  Fort  Bridger,  Wj^oming. 

The  remains  of  this  specimen  consist  of  portions  of  the  skull,  cervical 
and  dorsal  vertebrae,  and  a  tibia. 

The  second  specimen  (number  1266)  was  found  by  Messrs.  J.  W. 
Chew  and  L.  Lamotte,  in  August,  1874,  in  Wyoming.  It  consists  of 
portions  of  a  skull,  and  a  few  other  bones. 

The  geological  horizon  of  this  species  is  in  the  Dinoceras  beds  of  the 
Middle  Eocene. 

The  known  remains  of  this  species  are  preserved  in  the  Yale  College 
Museum. 


204 


DINOCERATA. 


Tinoceras  affliie,  Marsh,  n.  s. 

Woodcuts:   ]G,  ]).  19;  and  178,  1Y9,  below. 


PiGUEE  I'TS  — Vertical  EecUon  through  cranium  of  linoceras  ajfine.  Marsh  (No.  IS 
Figure  179.— The  same  specimen  ;  seen  from  above. 

ps.  parietal  supra-occipilal  suture;  fp.  fronto-parietal  suture;  o.  occipital  condyle:  ol.  olfactory  lobes  of 

brain ;  p'.  parietal  protuberance  ;  s.  supra-occipital  crest. 

Both  figures  are  one-eighth  natural  size. 

In  the  type  of  this  species  (immber  1574),  the  snout  tapers,  and  the 
nasals  are  divided  by  a  distinct  median  suture. 

The  nasals  are  well  preserved,  and  much  resemble  those  of  number  lO-ll, 
but  are  more  perfect.  As  in  number  1040,  they  are  thoroughly  co-ossified 
to  the  extreme  point,  which  is  directed  obliquely  downward.  The  nasal 
protuberances  are  placed  obliquely,  and  are  flattened  on  their  outer 
anterior  surface.  They  are  directed  outward  and  upward,  and  are  elongate- 
oval  in  section,  the  long  axes  of  the  ovals  making-  about  a  right  angle  with 
each  other  in  front  of  the  snout. 

The  maxillaiy  protuberances  are  elevated,  but  of  moderate  size,  and 
are  connected  across  by  a  rounded  ridge.  The  parietal  protuberances 
present  a  moderately  sharp  ridge  on  their  anterior  faces,  and  are  somewhat 
club-sliaped.  They  were  connected  across  the  top  of  the  skull  by  a 
rounded  ridge. 

The  foramen  magnum  is  transversely  oval,  and  rises  nearly  to  the 
same  heiglit  as  the  occipital  condyles.     The  post-glenoid  process  is  robust. 

The  occipital  crest  bears  a  rather  prominent,  but  rounded,  ridge  along 
the  median  line,  above  the  foramen  magnum. 

The  palate  is  moderately  excavated  in  front,  and  the  palato-maxillary 
foramen  is  opposite  the  first  premolar.  The  diastema  is  thick,  strong, 
sliort,  and  straight.  The  vomer  is  preserved  in  this  specimen,  finnly 
lodged  in  a  groove  in  the  upper  surface  of  the  maxillaries 


SYNOPSIS.  205 

The  face  on  the  zygomatic  process  of  the  squamosal  for  the  malar  is 
broad  and  flat,  and  does  not  end  in  a  pit,  for  the  posterior  end  of  the 
malar  bone. 

In  this  species,  the  brain  occupies  a  very  oblique  position  in  the  skull, 
as  shown  in  the  accompanying  woodcut,  figure  178.  In  the  section  of  the 
cranium,  the  sutures  defining  the  anterior  and  posterior  limits  of  the 
parietal  bones  along  the  median  plane  of  the  skull  are  clearly  shown. 
The  fronto-parietal  suture  also  (figure  178)  is  apparent  on  the  superior 
surface  of  the  skull,  above  the  anterior  part  of  the  cavity  for  the  cerebral 
hemispheres,  as  in  Dinoceras  distans  (number  1601).  The  suture  limiting 
the  parietal  posteriorly  is  evident  in  the  same  section.  It  is  behind  the 
cerebral  cavity,  but  cannot  be  traced  witli  certainty  on  the  upper  surface 
of  the  skull. 

The  type  specimen  (number  1574)  of  this  species  was  obtained  by 
Mr.  J.  Heisey,  eight  miles  south  of  Dug  Springs,  Wyoming,  in  1876. 

This  specimen  consists  of  a  skull,  etc. 

The  geological  horizon  is  in  the  Dinoceras  beds  of  the  Middle  Eocene. 

The  only  known  remains  of  this  specimen  are  in  Yale  College  Museum. 


Tlnoceras  aiinectens,  Marsh. 

Woodcuts:  6,  p.  13;  21,  p.  21;  36,  37,  p.  36. 

Marsh,  Fifth  Annual  Report  U.  S.  Geological  Survey,  (figures  from  the  jiresent  volume, 
viz:)  fig.  43,  p.  258;  fig.  56,  p.  264;  fig.  73,  74,  p.  274,  1884. 

The  skull  in  the  type  of  this  species  (number  1043)  agrees  generally 
in  size  and  form,  as  far  as  preserved,  with  that  of  Tinoceras  ingens,  (number 
1041).  The  canine  tusk  runs  somewhat  forward  in  number  1043,  and  the 
premaxillaries  appear  less  robust.  The  palato-maxillary  foramen  is  near 
the  front  premolar,  not  well  in  front  of  it,  as  in  Tinoceras  ingens.  The 
upper  canine  (page  21,  figure  21)  has,  on  its  outer  side,  a  large,  somewhat 
heart-shaped,  worn  surface. 

The  lower  jaw  in  this  species  is  slender,  and  bears  a  well  developed 
process  running  downwai-d  and  forward,  and  terminating  in  an  oblique, 
nearly  straight  margin.     Tlie  coronoid  process  is  pointed. 

The  first  dorsal  in  this  specimen  is  proportionally  shorter  than  in 
Tinoceras  anceps,  with  the  lateral  faces  for  its  ribs  more  approximate.  The 
length  of  the  floor  of  the  neural  canal  is  to  the  length  of  the  under  surface 
of  the  centrum  as  3  to  4,  and  a  similar  proportion  in  the  adjoining 
vertebra  indicates  an  upward  curvature  in  the  neck  at  this  point. 


206 


DINOCERATA. 


The  type  of  this  species  (number  1043)  was  found  by  Mr.  J.  Heisey, 
in  May,  1874,  near  Haystack  Mountain,  Wyoming. 

The  remains  consist  of  a  skull,  aud  other  portions  of  the  skeleton. 

^riie  geological  horizon  is  in  the  Bridger  beds  of  the  Middle  Eocene. 

The  only  known  specimen  of  this  species  is  in  the  Yale  College 
Museum. 

Tiiioceras  coriiutum.  Cope,  sp. 

Woodcuts:    180,  IS  1,  below. 


Figure  1  SO. — Skull  of  Tinoceras  cornuium,  Cope,  sp. ;  side  view. 


This  figure  and  the  following  were  jDhotographed  on  wood  from  Prof 
Cope's  original  photographs,  for  which  the  author  is  indebted  to  the  late 
Pi'of  Louis  Agassiz.  These  photographs,  although  both  mai'ked  \,  are  not 
of  the  same  size.  The  present  figures  are  copies,  both  reduced  in  the 
same  proportion.  The  white  portion  at  the  base  of  the  tusk  is  plaster,  and 
the  tooth  is  thus  made  to  appear  longer  than  in  nature.  The  tusk  itself 
belongs  on  the  other  side. 


SYNOPSIS. 


207 


Fig.  181. 


Figure  181. — Skull  of  Tinoceras  cornutum.  Cope,  sp.;  seen  from  below. 

Both  figures  are  about  one-eighlh  natural  size. 

Cope  (Lefalophodon  dicornutus). — Proceedings  of  the  American  Philosophical 

Society,  Vol.  XII,  p.  515,  for  1872.     1873. 
Telegram  from  Black  Buttes,  Wyoming,  October,  1872. 
The  same,  I'ala3ontological  Bulletin,  No.  5,  .Second  Edition,  1873. 
(Eobasileus  eornutus.) — Notices  of  new  Vertebrates  from  the  upper  waters  of 

Bitter  Creek,  Wyoming,  November,  1872. 
Proceedings  of  the  American  Philosophical  Society,  Vol.  XII,  p.  485,  for  1872,  1873. 
The  same,  Palfeontological  Bulletin,  No.  6,  1873. 
American  Natur.alist,  Vol.  VI,  p.  774,  December,  1872;  Vol.  VII,  p.  49,  January,  1873; 

Vol.  VII,  pp.  158,  159,  March,  1873. 
Hayden's  Report  of  the  tj.  S.  Geological  Survey  for  1873,  p.  457,  1874. 
(Loxolophodon     eornutus.) — Proceedings    of    the    American    Philosophical 

Society,  Vol.   XII,  jjp.  488  and  580,  for    1872,  1873;    Vol.  XIII,  pp.   45-54,  Plates 

I-IV,  1873. 
American  Naturalist,  Vol.  VII,  p.  291,  Plates  IV,  V,   May,  1873;  Vol.  XIII,  p.  334, 

May,  1879;  Vol.  XVI,  Plate  XVII  (Restoration),  December,  1882. 
Hayden's  Report  of  the  U.  S.  Geological  Survey  for  1872,  pp.  5G8-575,  Plates  1-4, 1873. 
Osborn,  Mem<iir  up)on  Loxolophodon  and  Uintatherium,  pp.  18,  20,  21,  27,  37,  44,  1881. 
Osborn  and  Speir,  American   Journal   of  Science  (3),  Vol.  XVII,  pp.  304-309,  Plate  I, 

April,  1879. 
Leidy  (Uintatherium    cornutum). — Extinct  Vertebrate   Fauna,   pp.    333,  334, 

1873. 
Marsh  (Tinoeeras  eornutus). — American  Journal  of  Science  and  Arts  (3),  Vol. 

V,  pp.  296,  311,  April,  1873. 
(Tinoeeras  grande.) — American  Journal  of  Science  and  Arts  (3),  Vol.  V,  p.  294, 

April,  1873. 
American  Naturalist,  Vol.  VII,  p.   217,  April,    1873;    Vol.  VII,   p.    306,  May,   1873; 

Vol.  VII,  Appendix,  p.  ii,  June,  1873. 
Proceedings  of  the  American  Philosoj)hical  Society,  Vol.  XIII,  p.  255,  1873. 

In  the  restoration  of  this  species  as  given  by  Professor  Cope 
in  the  American  Naturalist,  Vol.  XVI,  Plate  XVII,  the  skull  used  is 
the  male  one  here  figured,  with  the  tusk  much  elongated.  The  lower  jaw 
below  it  belonged  to  a  female,  possibly  of  another  genus.  The  scapula, 
as  restored,  is  unlike  that  of  any  of  the  known  Dinocerata,  and  the  entire 
fore  limb  is  in  a  position  anatomically  impossible. 


208  DINOCERATA. 

The  type  of  the  present  species  was  obtained  by  Prof.  E.  D.  Cope  and 
Mr.  S.  Smith,  in  August,  1872,  at  Haystack  Mountain,  Wyoming. 

The  remains  consist  of  portions  of  a  skull,  and  other  parts  of  the 
skeleton. 

The  skull  as  here  figured  is  in  the  collection  of  Prof.  Cope.  Some 
other  ])ortions  of  the  same  skull  and  skeleton,  subsequently  collected  by 
Mr.  S.  Smith,  are  in  the  Yale  Museum 


Tinoceras  crassifruns,  Marsh. 

Woodcuts:  30,  p.  29;  and  182,  below. 


FiGDRE  182. — Nasals  ul  Tinoceras  crassifrons,  Marsh  (Xo.  1  JJCj. 
a.  side  view;  b.  top  view;   c.  front  view. 

One-fifth  natural  size. 

Marsh,  Fifth  Annual  Report  of  the  U.  S.  Geological  Survey,  (figure  from  the  present 
volume,  viz:)  fig.  65,  y>.  270,  1884. 

The  nasals  in  the  type  of  this  species  (nnmber  1236)  bear  small,  but 
prominent,  tubercles,  directed  well  upward  and  outward,  and  placed  well 
back.  In  front  of  these  elevations,  the  nasals  are  produced,  and  terminated 
by  oblique,  but  nearly  vertical,  sutural  surfaces  for  tlie  pre-nasals. 

The  maxillary  protuberances  are  high  and  prominent,  and  connected 
by  a  transverse,  elevated,  and  sharp,  ridge. 

The  upper  surface  of  the  skull  is  flattened,  and  well  separated  from 
the  lateral  surfaces  by  a  ridge,  gradually  rising  into  the  parietal 
2Drotuberances.  Tliese  protuberances  are  connected  by  a  distinct 
transverse  ridge,  and  are  elevated,  and,  in  section,  somewhat  triangular. 

The  olfactory  lobes  of  the  brain  were  short,  and  the  olfactory 
chambers  were  not  divided  by  a  transverse  bony  septum. 

The  type  specimen  (number  1236)  of  this  species  was  collected  by 
Messrs.  L.  Lamotte  and  J.  W.  Chew,  at  Cattail  Springs,  about  twenty-five 
miles  southeast  from  Fort  Bridger,  and  about  eighteen  miles  west  of  Green 
River,  Wyoming,  July,  1874. 


SYNOPSIS. 


■209 


The  remains  of  this  specimen  consist  of  various  portions  of  a  skull. 
The  geological  horizon  is  in  the  Dinoceras  beds  of  the  Middle  Eocene. 
The  known  remains  of  this  species  are  in  the  Museum  at  Yale  College. 


Tinoceras  galeatum,  Cope,  sp. 

Woodcuts:   18.3  and  184,  below. 

riCr    184  Ftg.  183. 


Figure  183. — Xasals  of  Tinoceras  galtatam  (iifter  Cope);   a.  side  view;   b.  top  view. 
Figure  184. — Posterior  surface  of  same  skull. 

Both  figures  are  one-eighth  natural  size. 

These  figures  were  photogra^ihed  on  wood  from  the  lithographic  plate, 
cited  below. 

Cope  (Eobasileus  galeatus). — Hayden's  Report  U.  S.  Geological  Survey  for  1873, 

pp.  456,  457,  Plate  I,  1874. 
Proceedings  of  the  American  Philosophical  Society,  Vol.  5IV,  p.  17,  1874. 
(Loxolophodon  galeatus.)  — Hayden's  Report  U.  S.  Geological  Survey  for  1873, 

Plate  I,  1874. 
Osborn,  Memoir  upon  Loxolophodon  and  Uintatherium,  pjj.  21,  22,  1881. 

The  specimen  upon  which  this  species  was  based  was  obtained  by 
Prof  E.  D.  Cope,  in  1873,  in  the  Bad  Lands  of  South  Bitter  Creek, 
Wyoming. 

The  remains  consist  of  various  portions  of  the  skull. 

The  geological  horizon  is  in  the  Bridger  beds  of  the  Middle  Eocene. 

The  known  remains  are  preserved  in  Prof  Cope's  collection, 

27 


210 


DINOCERATA. 


Tinoceras  graiule,  Marsh. 


Woodcuts:   20,  p.  21;  49,  p.  44  ;   84,  85,  86,  p.  71;   87,  88,  p.  75  ;  and  185,  below. 

Fis,  ]85. 
b. 


\iiiUi4(/ 


Figure  185. — Nasals  of  Tinoceras  grande,  Marsh  (No.  1040). 
a.  side  view  ;  b.  top  view  ;  c.  front  view. 

One-fifth  natural  size. 


Marsh,  American  Journal  of  Science,  Vol.  IV,  p.  323,  October,  1872;  Vol.  V,  pp.  295, 
311,  April,  1873. 
American  Naturalist,  Vol.  VII,  p.  217,  April,  1873. 

Proceedings  of  the  American  Philosophical  Society,  Vol.  XIII,  p.  256,  1873. 
Fifth  Anniial  Rejjort  of  the  TJ.  S.  Geological  Survey,  (figures  from  the  present  volume, 
viz:)  fig.  55,  p.  264;   86,  p.  280  ;   1  13,  114,  115,  1  18,  119,  p.  295,  1884. 
Cope,  Proceedings  of  the  American  Philosophical  Society,  Vol.  XIII,  pp.  54,  61,  1873. 
(Loxolophodon    cornutus). — Hayden's   Report   U.  S.  Geological   Survey  for 
1872,  p.  575,  1873. 

The  tyj)e  specimen  (number  1040)  of  this  species  was  collected  at 
Barrel  Springs,  about  seventy-five  miles  east  of  Green  River,  Wyoming, 
in  1872,  by  Messrs.  J.  W.  Chew  and  B.  D.  Smith. 

The  remains  of  this  specimen  consist  of  portions  of  the  skull,  and 
cervical  vertebri3e. 

The  geological  horizon  of  this  sjaecies  is  in  the  Middle  Eocene,  in  the 
Dinoceras  beds. 

The  known  remains  are  preserved  in  Yale  College  Museum. 


Tluoceras  liians,  Marsh. 

Woodcuts:  32,  i>.  30;  and  186,  below. 


FiGTJRB  186. — ^Nasals  of  Tinoceras  Mans,  Marsh  (No.  1499). 
a.  side  ■view;  5.  top  view;  c.  front  view. 

One-fifth  natural  size 


SYNOPSIS.  211 

Marsh,  Fifth  Annual  Reijort  of  the  U.  S.  Geological  Survey  (figure  from  the  present 
volume),  fig.  67,  p.  211,  1884. 

The  snout  in  tlie  type  of  this  species  (number  1499)  tapers  in  front, 
where  the  nasals  are  divided  by  persistent  sutures,  and  bear  low  rounded 
tubercles.  The  maxillary  protuberances  are  connected  by  a  low  rounded 
ridge.  The  upper  surface  of  the  skull  behind  these  protuberances  is 
flattened,  and,  in  the  region  of  the  fronto-nasal  sutures,  elevated.  It  is 
separated  from  the  lateral  surface  by  a  ridge,  rising  gradually  upon  the 
parietal  protuberances,  which  are  connected  by  a  transverse  elevation 
across  the  sktill,  above  the  brain  case. 

The  olfactory  chambers  were  divided  transversely  by  a  bony  septum 
as  shown  in  figure  32,  page  30. 

The  palato-maxillary  foramen  extends  back  nearly  to  the  middle  of 
the  second  premolar.  The  premaxillaries  are  proportionally  larger  than 
in  Dinoceras  laticeps  (number  1039),  and  straighter  tlian  in  Dinoceras 
mirabile  (number  1036).  They  present  pits,  as  if  for  rudimentary  teeth, 
as  in  number  1039. 

This  species  is  based  upon  a  specimen  (number  1499)  collected  in 
June,  1874,  by  Mr.  L.  Lamotte,  at  Cattail  Springs,  Wyoming. 

The  remains  of  this  specimen  consist  of  a  skull,  vertebrae,  etc. 

The  geological  horizon  is  in  the  Dinoceras  beds  of  the  Middle  Eocene. 

The  known  remains  of  this  species  are  preserved  in  the  Museum  of 
Yale  College. 


Tinoceras  ingeiis,  Marsh. 

(Plates  XV-XVIII,  LVI.) 

Woodcuts:   9,  p.  16;   17,  p.  19;  23,  p.  25;  28,  p.  27;  51,  p.  45;  59,  p.  55;   115,  116,  p.  105; 
117,  p.  108;   124,  13.  119;   134,  135,  p.  136;   141,  142,  p.  149. 

Marsh,  Fifth  Annual  Report  of  the  U.  S.  Geological  Survey,  (figures  from  the  present 
volume,  viz:)  figs.  46,  j).  261;  52,  p.  263  ;  58,"p.  267;  63,  p.  269;  88,  p.  281;  96,  97,  p. 
286;  126,  127,  p.  297;  137,  p.  302,  1884. 

The  type  specimen  (number  1041)  of  this  species  was  collected  by 
Mr.  S.  Smith,  near  Haystack  Mountain,  Wyoming,  in  May,  1875. 

This  specimen  consists  of  a  skull,  in  excellent  preservation. 

The  geological  horizon  of  this  species  is  in  the  Dinoceras  beds  of  the 
Middle  Eocene. 

The  known  remains  of  this  species  are  in  Yale  College  Museum. 


212 


DINOCERATA. 


Tinoceras  jiigum,  Marsh. 

Woodcut:   187,  below. 


Figure  187. — Nasals  of  Tinoceras  jugum.  Marsh  (No.  1500). 
a.  side  view ;  J.  top  view  ;  c.  front  view. 

One-fifth  natural  size. 

In  this  species,  the  snout  tapers  forward,  and  bears  a  pair  of  small 
flattened  tubercles,  directed  well  outward  and  forward.  The  nasals  are 
thoroughly  coossified,  and  project  in  front  beyond  the  tubercles.  The 
maxillary  protuberances  are  high,  and  strongly  divergent.  They  are 
connected  by  a  hig'h  sharp  ridge,  which  suggested  the  specific  name. 

The  tyjje  of  this  species  (number  1500)  was  found  iDy  Mr.  L.  Lamotte, 
in  September,  1874,  in  Wyoming. 

The  specimen  consists  of  portions  of  the  skull,  and  fore  limbs. 

The  geological  horizon  is  in  the  Bridger  beds  of  the  Middle  Eocene. 

The  only  remains  known  are  in  the  Yale  Museum. 

Tinoceras  laciistre,  Marsh. 

Woodcut:  188,  below. 

Fig.  \i 


FieuEE  188. — Upper  molars  of  Kjioceras  ?oc«sfoe,  Marsh  (No.  1037);   seen  from  below. 
m.  first  true  molar,';  pm.  first  premolar. 

Three-fourths  natural  size. 

Marsh  (Dinoeeras  lacustris). — American  Journal  of  Science  and  Arts  (3),  Vol.  IV, 
p.  344,  October,  18'72. 
Proceedings  of  the  American  Philosophical  Society,  Vol.  XIII,  p.  266,  1870. 
Cope  (Uintatherium  lacustre). — Hayden's  Report  U.  S.  Geological  Survey  for 
1872,  pp.  581,  584,  1873. 
Proceedings  of  the  American  Philosophical  Society,  Vol.  XIII,  pp.  61,  66,  1873. 


SYNOPSIS. 


213 


The  type  specimen  (number  1037)  of  this  species  was  discovered  by 
Messrs.  J.  W.  Chew  and  B.  D.  Smith,  near  Bitter  Creek,  Wyoming,  in  1872. 

This  specimen  consists  of  upper  premolars,  molars,  and  a  radius. 

The  geological  horizon  is  in  the  Bridger  beds  of  the  Middle  Eocene. 

The  known  remains  of  this  species  are  preserved  in  the  Museum  of 
Yale  College. 

Tinoceras  latum,  Marsh,  n.  s. 

Woodcuts:   189  and  190,  below. 


Fi&UEE  189. — Nasals  of  Tinoceras  latum,  Marsh  (No.  li-i'l). 
a.  side  view ;  b.  top  view ;  c.  front  view. 

ODe-fifth  natural  size. 


FiGtJPb  190  —  Nisilsof  y/«f  eius  latum.   Mirsh  (No   ISSO) 
a  side  view ,   6  top  view ,  c  front  view 

One-fifth  natural  size. 

The  snout  in  the  type  specimen  of  this  species  tapers  toward  the  end, 
but  bears  a  pair  of  low  rounded  tubercles,  directed  nearly  forward,  and 
only  slightly  outward  or  upward.  They  are  separated  in  front,  along  the 
median  line,  by  an  open  suture  between  the  nasal  bones.  These  project 
forward  beyond  the  protuberances,  and  terminate  differently  on  the  two 
.sides,  the  left  coming  nearly  to  a  point,  while  the  right  is  a  little  shorter, 
and  ends  with  an  oblique  sutural  surface. 

The  skull  presents  a  transverse  ridge  above  the  brain  cavity,  uniting 
the  parietal  protuberances. 


214 


DINOC'ERATA. 


The  teeth  preserved  are  but  h'ttle  worn,  indicating  a  fully  adnlt,  but 
not  old,  animal. 

Another  specimen  (nnmber  1533)  referred  to  this  species  is  quite 
unlike  any  other  in  the  collection  in  the  form  of  the  nasal  bones  so  far  as 
preserved,  but,  unfortunately,  the  specimen  is  considerably  eroded.  The 
snout,  instead  of  tapering,  expands  forwaixl,  and  presents  on  each  side  a 
broadly  rounded,  horizontal  protuberance,  scarcely  rising  at  all  above  the 
general  level  of  the  nasal  bones.  They,  also,  project  forward,  far  beyond 
the  end  of  those  bones,  Avhich  were  thoroughly  consolidated,  and  directed 
somewhat  downward,  underneath  the  broad  shelving-  jn'otuberances. 

The  left  maxillary  protuberance  preserved  with  this  specimen  is  of 
large  size,  and  flattened  on  its  outer  side. 

This  species,  with  Tiuoceras  cornutum,  forms  a  distinct  sub-genus  of 
Tinoceras,  A^'hich  may  be  called  Plafoceras. 

The  type  of  this  species  (number  1242)  was  obtained  in  September, 
1873,  by  Mr.  L.  Lamotte  and  the  author,  near  Spanish  John's  Meadow, 
Wyoming. 

The  remains  of  this  specimen  consist  of  portions  of  the  skull,  and  teeth. 

A  second  specimen  (number  1533),  apparently  a  very  old  individual 
of  the  same  species,  was  found  in  Ma}^,  1875,  by  Messrs.  S.  Smith  and 
S.  Pearson,  at  Haystack  Mountain,  Wyoming. 

This  specimen  consists  of  portions  of  the  skull.  The  extremity  of 
the  nasal  bones  is  figured  above. 

The  geological  horizon  of  these  specimens  is  in  the  Bridger  beds. 

The  known  remains  of  this  species  are  preserved  in  Yale  College 
Museum. 


Tinoceras  longiceps,  Marsh. 

Woodcuts:  38,  p.  37;  48,  p.  43;  and  191,  192,  below. 

Fig.  19-'. 


Figure  191. — Loft  maxillary  protubei-anco  of  Tinoceras  longiceps,  Marsh  (No.  1256,  female);  side  view. 
Figure  192. — Left  parietal  protuberance  of  same  skull ;  side  view. 

The  dotted  line  shows  the  outline  of  the  caviiies  {a  and  b)  at  the  base  of  each  specimen. 
Both  figures  are  one-iourth  u.atural  size. 


SYNOPSIS.  215 

Marsh,  Fifth  Annual  Report  of  the  U.  S.  Geological  Survey,  (figures  from  the  present 
volume,  viz:)  fig.  75,  p.  275;  85,  p.  279,  1884. 

The  skull  in  this  species  presents  some  striking  peculiarities.  The 
maxillary  protuberances  are  placed  well  back,  and  are  much  above  the 
socket  for  the  weak  and  slender  canine  tooth  (figure  48,  page  43).  They 
are  directed  upward  and  outward,  and  ai-e  greatly  excavated  within,  and 
below,  as  shown  in  figure  191.  The  parietal  protuberances  are  well 
developed,  and  are  also  excavated  near  the  base.  The  anterior  face,  as  far 
as  preserved,  shows  no  distinct  indication  of  a  sharp  ridge  rising  on  the 
frontal  bone  in  front  of  the  protuberance,  as  in  Dinoceras  laticeps  (number 
1202),  but  the  parietal  protuberances  seem  to  have  risen  abruptly,  as  in 
Tinoceras  ingens.  They  are  flatteiied  behind,  but  are  scarcely  expanded 
transversely,  as  in  the  males  of  this  type.  The  zygomatic  process  of  the 
squamosal  is  slender,  and  presents  a  decided  pit  for  the  posterior  end  of 
the  malar,  just  in  front  of  the  glenoid  cavit}^. 

The  lower  jaw  (figure  38,  page  37)  is  elongated,  and  presents  a  small 
and  weak  pendent  process,  for  the  protection  of  the  small  and  slender 
canine  tusk  (figure  48,  page  43).  This  tusk  has  a  nearly  straight  root, 
which  suddenly  contracts  at  the  apex  into  a  small  orifice.  The  position 
of  its  socket  is  well  in  front  of,  and  below,  the  maxillary  horn-core,  and 
unlike  that  of  any  other  specimen  in  the  Museum. 

This  species  is  based  upon  a  specimen  (number  1256,  female)  obtained 
b)^  Mr.  J.  Heisey,  at  Red  Dog  Buttes,  Wyoming,  in  June,  1876. 

The  remains  of  the  type  of  this  species  consist  of  portions  of  the 
skull,  lower  jaws,  etc. 

The  geological  horizon  is  in  the  Dinoceras  beds  of  the  Middle  Eocene. 

The  known  remains  of  this  species  are  in  Yale  College  Museum. 

Tinoceras  pugnax,  Marsh. 

(Plate  XIX.) 

Woodcuts:  5,  p.  13;  18,  p.  19;   19,  p.  21;  24,  p.  25;  29,  p.  27  ;  52,  p.  45;  67,  p.  63. 

Marsh,  Fifth  Annual  Report  of  the  IT.  S.  Geological  Survey,  (figures  from  the  present 
volume,  viz:)  fig.  42,  p.  258;  53,  p.  263;  54,  p.  264;  59,  p.  267;  64,  p.  269;  89, 
p.  282;   104,  p.  290,  1884. 

The  type  specimen  of  this  species  (number  1044)  was  an  individual 
of  moderate  size,  and  a  male.  The  skull  is  short,  and,  seen  from  above 
strongly  wedge-shaped.  The  nasal  protuberances  are  small,  high,  and 
widely  separated.  The  maxillary  elevations  are  somewhat  in  front  of  the 
diastema.  They  are  robust  and  recurved.  The  parietal  protuberances  are 
of  moderate  height,  and  transversely  compressed  at  their  summits.  The 
premaxillaries  are  widely  separated  in  front.  The  palato-maxillary 
foramen  is  opposite  the  second  premolar.  The  posterior  nares  open 
upward  through  oval  apertures,  but  little  behind  the  bony  palate.     The 


216 


DINOCERATA. 


palate  is  much  expanded  between  the  canine  tusks.  The  lower  jaw  has 
the  alveoles  of  the  incisors  and  canines  nearly  vertical.  The  flange  for 
protection  of  the  tusk  is  long-,  and  rounded  in  front  (Plate  XIX,  figure  1). 

This  specimen  represents  a  distinct  sub-genns  of  Tinoceras,  which  may 
be  called  Laoceras. 

The  type  specimen  (number  1044)  of  this  species  was  found  by  Mr. 
S.  Smith,  May,  1875,  at  Haystack  Mountain,  Wyoming. 

This  specimen  consists  of  a  sknll  in  good  condition,  and  various  other 
bones  of  the  same  individual. 

The  geological  horizon  of  this  specimen  is  in  the  Dinoceras  beds. 

The  known  remains  of  this  species  are  preserved  in  the  Museum  of 
Yale  College. 

Tinoceras  Speiriaiiiim,  Osborn,  sp. 

Woodcut:   193,  below. 


-lOmiE  19    — SI  nil  of  Tmoteias  Sj  t 


I     M   u  (    I  ei  O  1  Clb 
Out  eighth  mtui  il  &izp 


Osborn     (Loxolophodon     Speirianum). — Memoir     upon    Loxolophodon     and 
Uintatheriura,  pp.  18,  20,  21,   22,  24,  41,  44,  Plate  I,  18S1. 

This  figure  was  photographed  on  wood  from  the  lithographic  plate 
cited  above.  The  restorations  of  this  skidl  do  not  allow  some  of  its 
important  features  to  be  determined,  but  the  generic  characters  ai-e  distinct. 

In  the  restoration  of  this  species,  as  given  in  the  work  cited  above, 
the  skull  belonged  to  a  male,  and  the  lower  jaw  to  a  female.  The  bones 
of  the  fore  limb,  also,  are  in  a  position  impossible  in  life. 

The  type  specimen  of  this  species  was  discovered  by  Mr.  Francis 
Speir,  in  1878,  in  Wyoming. 

This  specimen  consists  of  the  skull  here  figured. 

The  geological  horizon  is  in  the  Bridger  beds  of  the  Middle  Eocene. 

The  known  remains  of  this  species  are  in  the  Princeton  Museum. 


SYNOPSIS. 

Tlnoceras  stenops,  Marsh. 

Woodcuts:  58,  54,  p.  4V;  and  194,  below. 
Fig.  194. 


217 


Figure  194. — Skull  and  lower  jaw  of  Tinoceras  stenops,  Marsli  (No.  156T). 

e.  condyle  of  lower  jaw;  d.  diastema;  m'.  maxillary  protuberance;   n'.  nasal  protuberance;  o.  occipital 
condyle;  p'.  parietal  protuberauce ;  pm.  premaxillary  lione. 
One-eighth  natural  size. 

Marsh,  Fifth  Annual  Report  of  the  U.  S.  Geological  Survey  (figures  from  the  present 
volume,  viz:)  fig.s.  90,  91,  p.  283,  1884. 

The  skull  in  the  type  specimen  of  this  species  (number  1567)  is 
narrow,  and  elongated.  The  nasal  protuberances  are  flat  below,  and 
above.  They  appear  to  have  been  divergent,  but  of  moderate  size, 
though  situated  well  forward.  The  maxillary  protuberances  were 
prominent,  directed  well  forward,  and  connected  by  a  transverse  ridge. 
Behind  them,  on  each  side,  stands  a  prominent  protuberance  over  the 
orbit.  Back  of  this,  the  superior  and  lateral  surfaces  of  the  skull  pass 
into  each  other  by  regular  curvature  in  front  of  the  origin  of  the  latei'al 
ridges,  which  rise  abruptly  upon  the  parietal  protuberances.  These 
elevations  are  imperfectly  preserved,  but  are  flattened  in  front,  and 
situated  behind  the  post-glenoid  processes. 

28 


218  DINOCERATA. 

The  palate  is  excavated  in  tlie  region  of  tlie  diastema,  and  the 
palato-maxillaiy  foramen  is  just  in  front  of  the  first  premohir,  but  not 
so  far  in  front  as  in  Tiiioceras  ingens  (number  1041). 

The  lower  jaw  is  slender,  and  expands  rapidly  in  the  region  of  the 
symphysis  for  the  formation  of  the  flanges  pi'otecting  the  canine  tusks. 
When  seen  from  above,  the  nngle  at  .  which  the  rami  meet  at  the 
symphj^sis  is  distinctly  rounded  in  front,  though  somewhat  less  strongly 
than  in  JDinoceras  latkeps  (Plate  Xll,  figure  1). 

The  type  specimen  (nimiber  1567)  of  this  species  was  collected  by 
Mr.  S.  Smith,  at  Haystack  Mountain,  Wyoming,  in  May,  1882. 

The  remains  of  this  specimen  consist  of  a  skull,  with  lower  jaw,  etc. 

The  geological  horizon  of  this  species  is  in  the  Dinoceras  beds  of  the 
Middle  Eocene. 

The  known  remains  of  this  species  are  in  the  ^^ale  College  Museum. 


Tinoceras  vagaiis,  Marsh. 

"Woodeut:  12,  p.  IT. 

Marsh,  Fifth  Animal  Report  of  the  U.  S.  Geological  Survey,  (figure  from  the  present 
volume,  viz:)  fig.  49,  p.  26^,  1884. 

The  snout  in  the  type  of  this  species  (number  1241)  tapers  somewhat 
in  front,  and  the  nasal  protuberances  are  flattened  and  directed  forward, 
outward,  and  up\^■ard.  The  nasal  bones  are  united  throughout.  The 
maxillary  protuberances  are  slender,  but  prominent,  and  united  across  by 
a  low  rounded  ridge.  The  upper  surfnce  of  the  skull  is  separated  from 
the  lateral  surface,  above  and  fiehind  the  orbits,  by  a  ridge,  which  rises 
upon  the  parietal  protuberances.  These  are  prominent,  and  are  flattened 
antero-posteriorly.  They  were  connected  across  the  top  of  the  skull  by 
a  low  transverse  elevation. 

The  type  specimen  (number  1241)  of  this  species  was  discovered  by 
Mr.  S.  Pearson,  at  lied  Dog  Buttes,  AVyomiug,  in  July,  1875. 

Tliis  specimen  consists  of  portions  of  the  skull,  etc. 

The  geological  horizon  is  in  the  Dinoceras  beds  of  the  Middle  Eocene. 

The  known  remains  of  this  species  are  preserved  in  the  Yale  Museum. 


SYNOPSIS. 


219 


UINTATHERIUM,'  Leidy,   1872. 
Uiutjitliei'iiim  robiistiim,  Leidy. 

Woodcuts:  61,  62,  p.  51;  and  195,  below. 
rii    195 

muiiiiiiijh 


FinuRE  195. — Skull  of  Ulntathermm  rohmium,  Leidy  (type  specimen),  bottom  view  of  back  pan;  of  skull. 

/.  foramen  magnum;  /'.  oceipilal  foramen;  g.  stylo-mastoid  foramen;  h    foramen  lacerum  •  i.  vascular 
foramen  in  basisphenoid. 

One-fourlh  naturnl  size. 

Leidy,  Proceedings  of  the  Philadelphia  Academy  of  N.T,tiiral  Sciences,  pp.  169,  241,  1872 

American  Journal  of  Science  and  Arts  (;5),  Vol.  IV,  p.  240,  September,  1872. 

Extinct  Vertebrate  Fauna,  pp.  93,  06,  333,  334,  Plate  XXV,  Plate  XXVI    fio-s    1-8 
Plate  XXVII,  tigs.  3(i-34,  1873.  '     ^^ 

Cope,  Proceedings  of  the  Philadelphia  Academy  of  Natural  Sciences,  p.  102,  March  1873- 
p.  295,  for  1882,  1883.  '  '  ' 

Hayden's  Report  TJ.  S.  Geological  Survey  for  1872,  pp.  581,  583,  1873. 

American  Naturalist,  Vol.  VII,  p.  159,  March,  1873;  Vol.  XVII,  p.  68,  January,  1883. 

Proceedings  of  the  American  Philosophical  Society,  Vol.  XIII,  pp.  62,  64,  1873. 
.Alarsh,  American  Journal  of  Science  and  Arts,  Vol.  V,  p.  290,  April,  1873. 

American  Naturalist,  Vol.  VII,  p.  147,  March,  1873. 

Proceedings  of  the  American  Philosophical  Society,  Vol.  XII,  p.  578,  1872. 
Osborn,  Scott  and  Speir,  Palseontological  Keport,  1877,  pp.  62,  71,  82,  1878. 
Osborn,  Memoir  upon  Loxolophodon  and  Uintatheriura,  pp.  18,  28,  1881. 
Leidy  (Uintamastix  atrox). — Extinct  Vertebrate  Fauna,  pp.  94,  107,  333,  1873. 

The  type  specimen  of  this  species  was  collected  iu  1872,  by  Drs. 
J.  V.  A.  Carter  and  J.  K.  Corson,  fifty  miles  east  of  Fort  Bridg-er, 
Wyoming. 

The  remains  of  this  specimen  consist  of  the  cranial  portion  of  a  skull, 
with  fragments  of  both  jaws,  and  portions  of  limb  bones. 

The  geological  horizon  of  this  species  is  in  the  Bridger  beds  of  the 
Middle  Eocene. 

This  type  specimen  is  preserved  in  Prof  Leidy's  collection. 

'  Uinta,  Indian  name,  and  dijpiov,  a  wild  beast. 


220 


DINOCERATA, 


TJintatherium  flssidens,  Cope,  sp. 

Woodcuts:   196  and  197,  below. 


Fir.  191. 


FiftURE  193. — Lower  jaw  of  Uintatliernmi flssidens  (after  Cope);  top  view. 
Figure  107. — The  same  specimen ;  front  view. 

Both,  figures  are  two-lbirds  natural  size. 

The  above  fig-ures  were  made  by  a  direct  transfer  from  the  original 
woodcuts  cited  below. 

Cope    (Bathyopsis    flssidens). — Bulletin  of  the  U.  S.  Geological  Survey  of  the 

Territories,  Vol.  VI,  No.  1,  pp.  194-196,  February,  1881. 
Proceedings  of  the  American  Philosophical  Society,  Vol.  XX,  pp.  176,  177,  1882. 
American  "Naturalist,  Vol.   XV,  p.   75,  January,   1881;    Vol.  XVIII,  p.    1115,  fig.  7, 

November,  1884. 

The  type  specimen  of  this  species  was  collected  by  Mr.  J.  L.  Wortman, 
in  1880,  in  the  Wind  River  Basin,  Wyoming-. 

This  specimen  consists  of  portions  of  the  lower  jaws  here  figured. 

The  geological  horizon  of  this  species  is  not  known  with  certainty, 
but  is  apparently  in  the  Bridger  beds  of  the  Eocene. 

The  type  specimen  is  preserved  in  Prof  Cope's  collection. 


Uintatlieriiim  latifroiis.  Marsh. 

Woodcuts:   11,  p.  17;  125,  126,  127,  128,  p.  130. 

Marsh,  Fifth  Annual   Report  of  the  U.  S.  Geological   Survey,  (figure  from  the  present 
volume,  viz:)  fig.  48,  p.  262,  1884. 

In  this  species,  the  snout  tapers  in  front,  where  the  nasals  are  divided 
by  an  open  suture.  The  nasal  protuberances  are  of  moderate  size, 
broadly  oval  at  the  base,  approximate,  and  moderately  divergent.  The 
nasals  project  well  forward  beyond  them.  The  maxillary  protuberances 
are  large,    and  I'ounded,    and    ai-e   connected  by  a  very  low    transverse 


SYNOPSIS. 


221 


ridge.  Tlie  parietal  protuberances  were  robust,  and  broadly  oval  in 
section  near  the  top,  and  are  connected  by  a  low  transverse  ridge  across 
the  top  of  the  skull.  All  these  protuberances  in  this  specimen  are  smooth, 
and  regularly  rounded. 

The  type  specimen  (number  1231)  upon  which  this  species  is  based 
was  collected  by  Mr.  J.  W.  Chew,  in  1874,  two  miles  from  Big  Bone 
Buttes,  Wyoming. 

The  remains  of  this  specimen  consist  of  a  skull,  etc. 

The  geological  horizon  of  this  species  is  in  the  Dinoceras  beds  of  the 
Middle  Eocene. 

The  known  remains  of  this  species  are  preserved  in  Yale  College 
Museum. 


Uiiitatherium  Leidianum,  Osborn,  Scott,  and  Speir. 

Woodcut:   198,  below. 
Fig.  198. 


Figure  198. — Skull  of  Uintatherium  Leidianum  (after  0>'bom,  Scott,  aud  Speir) ;  oblique  side  view. 
About  cue-eighth  natural  size. 

This  figure  was  photographed  on  wood  from  the  original  heliotype 
plate,  cited  below. 

Osborn,  Scott,  and  Speir,  Palseontological  Report,  pp.  63-80,  Plates  VI-VIII,  1878. 
Osborn,  Memoir  upon  Loxolophodon  and  Uintatherium,  pp.  18,  19,  22-24,  Plate  II,  1881. 
Cope,  American  Naturalist,  Vol.  XVIII,  p.  1117,  tig.  10,  November,  1884. 

The  type  specimen  of  this  species  was  collected  in  1877,  near  Dry 
Creek,  in  Wyoming. 


222  DINOCERATA. 


This  specimen  consists  of  a  sknll,  and  portions  of  the  skeleton. 
The  geological  horizon  of  this  species  is  in  tlie  Dinoeeras  beds  of  the 
Middle  Eocene. 

The  ty^je  specimen  is  preserved  in  the  Princeton  Museum. 


Uinta  til  eiiuiii  segue,  Marsh. 

Woodcuts:   41,  42,  p.  39;   101,  102,  p.  S3;   and  199,  200,  below. 

T.      -,n^  '  Fis-  200. 

Fig.  199. 


j! 


Figure  199. — Maxillary  protuberances  of  Uintatherium  segne,  Marsh  (NTo.  1194);  seeu  from  above. 
FiGUEE  200. — Tlie  same  specimen;  seen  from  in  front. 
m'.  maxillary  protuberance ;  n.  nasal  bone. 

Both  figures  are  ooe-fouith  natural  size 

Marsh,  Fifth  Arniual  Report  of  the  XJ.  S.  Geological  Survey,  (figures  from  the  present 
volume,  viz:)  figs.  78,  79,  p.  276,  1884. 

The  maxillary  protuberances  of  the  skull  of  this  specimen  ore 
peculiar  for  their  robust  form.  They  are  connected  by  a  well  developed 
transverse  ridge.  The  parietal  protuberances  are  massive,  and  some\Yhat 
club-shaped,  and  present  a  ridge  in  front,  as  in  Dinoeeras  mirabUe  and 
Tiiioeeras  h?ffens,  evidently  formed  by  the  frontal  bone  rising  nearly  to 
the  top  of  the  protuberances. 

The  type  specimen  (number  1194)  of  this  species  was  collected  by 
Messrs.  S.  Smith  and  J.  W.  Chew,  east  of  Fort  Bridger,  AVj'oming,  in 
October,  1873. 

The  remains  of  this  species  consist  of  a  lower  jaw,  and  other  jjarts  of 
the  skeleton. 

The  geological  horizon  of  this  species  is  in  the  Dinoeeras  beds  of  the 
Middle  Eocene. 

The  known  remains  of  this  species  are  preserved  in  Yale  College 
Museum. 


SYNOPSIS.  223 

Ambiypoda,  see  Amblytlactyla. 

Bathyopsis  fissidens,  see  Uilltatlieriuill  flssldeilS. 

Dinoeerea,  see  DillOCerJlta. 

Dinoeeras  laeustris,  see  TinoceraS  lacilStre. 

Eobasileus  eornutus,   see  TillOCeraS   COl'llutlllU. 

Eobasileus  fureatus,  see  TillOCeraS. 

Eobasileus  galeatus,  see  TillOCeraS  galeatUlU. 

Eobasiliidas,  see  TillOCeratidse. 

Lefalophodon  bifureatus,  see  Tinoceras. 

Lefalophodon  exeressieornis,  see  TillOCd'aS. 

Lefalophodon  diseornutus,  see  TinoceraS  COrilutum. 

Loxolophodon  aneeps,  see  TillOCeraS  aiiceps. 
Loxolophodon  eornutus,  see  TillOCeraS  COrilUtlllU. 

Loxolophodon  fureatus,  see  TlllOCeraS. 

Loxolophodon  galeatus,  see  TillOCei'aS  galeatUIIl. 

Loxolophodon  grandis,  see  TillOCeras  grailde. 

Loxolophodon  pressieornis,  see   TillOCGFaS. 

Loxolophodon  Speirianum,  see  Tinocer.as  Speiriamim. 

Mastodon  aneeps,  see  TillOCeraS  aiiceps. 
Pantodonta,   see  CorypllOdoiltia. 
Titanotherium  ?    aneeps,  see  TillOCeraS  ailCepS. 

uintamastix  atrox,  see  UiiitatJieriiim  robiistum. 

Uintatherium  eornutum,  see  TlllOCeraS  COl'lllltum. 

Uintatherium  laeustre,  see   TillOCei'aS  laCUStre.     • 

Uintatherium  latieeps,  see  DlllOCeraS   laticepS. 

Uintatherium  prineeps,  see  ITintatheriuill. 

Uintatherium  lueare,  see  DillOCeraS  llicare. 

Uintatherium  mirabile,  see  DillOCeraS  lIlil'aMle. 

Uintatheridee,  see  TillOCeratidae. 


BIBLIOGEAPHT. 


1871. 

Marsh,  Othniel  Charles.— Notice  of  some  New  Fossil  Mammals  from  the  Tertiary 
Formation. — American  Journal  of  Science  and  Arts  (3),  Vol.  II,  pj).  35-44.  New 
Haven,  July,  1871. 

First  species  of  Dinocerata  described  (Titanotheriiim  ?  a-iceps).  TitanoUierium  was  the  tirst  generic 
name  applied  to  any  of  the  Dinocerata.  It  was  then  a  synonym  of  Menodus,  but  having  been 
once  used  in  another  grouij,  it  cannot  be  retained  for  any  geoiis  of  tlie  Dinocerata.  The  same 
well  known  rule  excludes  the  name  Loxolophodon,  which  was  first  given  to  a  species  of 
Coryphodon. 


1872. 

M-arshj  Othniel  Charles. — Preliminary  Descrijrtion -of  New  Tertiary  Mammals;  Part 
I. — American  Journal  of  Science  and  Arts  (3),  Vol.  IV,  pjj.  122-128.  New  Haven, 
August,  1872. 

The  same,  published  in  advance,  July  22,  1872. 

Abstract  of  same. — Neues  Jahrbuch  fur  Mineralogie,  etc.,  pp.  990,  991,  Stuttgart,  1872. 


Leidy,    Joseph.  —  On    some    New   Species    of    Fossil    Mammalia    from    Wyoming. 
Proceedings    of    the   Academy   of    Natural    Sciences,   Vol.    XXIV,    pp.    167-169. 
Philadelphia,  September,  1872. 
The  same,  published  in  advance,  August  1,  1872. 

The  same,  American  Journal  of  Science  and  Arts  (3),  Vol.  IV,  pp.  239,  240.     New 
Haven,  September,  1872. 

First  description  of  Uinfatherium  robnstum. 

29  225 


226  DINOCERATA. 

Marsh,  Othiliel  Charles. — Preliminary  Description  of  New  Tertiary  Mammals;  Parts 
I,  II,  III,  and  IV  (from  American  Journal  of  Science  and  Arts,  August  and 
September,  1872),  with  Postscript  and  Errata,  pp.  1-35;  published  in  advance, 
August  19,  1872. 

The  genus  Tinoceras  proposed. 


Marsh,  Othiliel  Charles. — Note  on  Tinoceras  anceps. — American  Journal  of  Science 
and  Arts  (3),  Vol.  IV,  p.  322.     New  Haven,  October,  1872. 
The  same,  jjublished  in  advance  August  24,  1872. 
Abstract  of  same.- — Popular  Science  Review,  p.  94,  London,  January,  1873. 


Marsh,    Othnlel    Charles. — Errata. — American   Journal   of    Science   and   Arts    (3), 
Vol.  IV,  fourth  i^age  of  cover,  September,  1872.     The  same,  p.  604.     New  Haven, 
December,  1872. 


Marsh,  Othiliel  Charles. — Notice  of  a  new  Species  of  Tinoceras. — American  Journal 
of  Science  and  Arts  (3),  Vol.  IV,  p.  323.     New  Haven,  October,  1873. 
The  same,  published  in  advance,  September  21,  1872. 

Description  of  Tinoceras  grande,  and  family  TinoceraiidcR  proposed. 


Marsh,  Othniel  Charles. — Notice  of  some  Remarkable  Fossil  Mammals. — American 
Journal  of  Science  and  Arts  (3),  Vol.  IV,  pp.  343,  344.     New  Haven,  October,  1872. 
The  same,  published  in  advance,  September  27,  1872. 

Sinoceras  mirdbile  and  S.  lacusire  first  described,  and  the  order  Dinooefi-ata  proposed. 


Cope,  Edward  Brlnker. — Notices  of  New  Vertebrata  from  the  Upper  "Waters  of 
Bitter   Creek,   Wyoming   Territory. — Proceedings  of    the  American   Philosophical 
Society,  Vol.  XII,  number  89,  for  1872,  pp.  483-486.     Philadelphia,  February,  1873.* 
The  same,  published  in  advance.     Philadelphia,  1872. 

*  The  authority  for  the  date  here  assigned  to  this  number  of  the  Proceedings  is  the  written  statement 
of  Prof.  J.  P.  Lesley,  Secretary  of  the  Society,  who  then  had  charge  of  its  publications. 


Cope,  Edward  Drinker. — Second  Notice  of  Extinct  Vertebrates  from  Bitter  Creek, 
Wyoming. — Proceedings  of  the  American  Philosophical  Society,  Vol.  XII,  number 
89,  for  1872,  pp.  487,  488.     Philadelphia,  February,  1873. 
The  same,  published  in  advance,  1872. 

Description  of  specimens  named  loxolophodon  cornutus,  L.  furcatus,  and  L.  pressicornis.     (See  note 
on  page  225  of  the  present  volume.) 


BIBLIOGRAPHY.  227 

Cope,  Edward  Drinker.— Notice  of  Proboscidians  from  the  Eocene  of  Southern 
"Wyoming. — Proceedings  of  the  American  Philosophical  Society,  Vol.  XII,  number 
89,  for  18T2,  p.  5S0.     Philadelphia,  February,  1873. 

The  same,  with  errors.  Telegram  from  Black  Buttes,  Wyoming,  published  in  advance, 
1872. 

The  same,  Palasontological  Bulletin,  No.  5,  re-published,  Philadelphia,  18'73. 


Cope,  Edward    Drinker.— The   Proboscidians  of   the  American   Eocene.— American 
Naturalist,  Vol.  VI,  pp.  773,  774.     Salem,  December,  1872. 


Leidy,  Joseph. — Remarks  on  Fossil  Mammals  from  Wyoming. — Proceedings  of  the 
Academy  of  Natural  Sciences,  Vol.  XXIV,  pp.  240-242.     Philadelphia,  December, 

1872. 


1873. 

Marsh,  Othniel  Charles. — On   some   of   Professor   Cope's   Recent   Investigations.- 
American  Naturalist,  Vol.  VII,  pp.  51,  52.     Salem,  January,  1873. 


Cope,    Edward    Drinker. — Proboscidians   of    the   American   Eocene,    Correction. 
American  Naturalist,  Vol.  VII,  p.  49.     Salem,  January,  1873. 


Marsh,  Othniel  Charles. — On  the  Gigantic  Fossil  Mammals  of  the  Order  Dinocerata. 
— American  Journal  of  Science  and  Arts  (3),  Vol.  V,  pp.  117-122,  Plates  I,  II.     New 
Haven,  February,  1873. 
The  same,  published  in  advance,  January  28,  1873. 

A  general  description  of  the  Dinocerata,  with  figures  of  the  skull  of  Dimceras,  and  corrections  of 
errors  in  Prof.  Cope's  publications  on  the  same  subject. 

Abstract  of  same. — Zeitschrift  filr  die  Gesammten   Naturwissenschaften,  vol.  vi,  pp. 

633,  534,  Berlin,  December,  1872. 
The  same. — Annales  des  Sciences  Naturelles  (Zoologie),  vol.  xvii,  23p.  1-8,  Paris   1873. 
The  same. — Journal  de  Zoologie,  vol.  ii,pi3.  160-168,  Paris,  1873. 
Abstract  of  same. — Geological  Magazine,  vol.  x,  pp.  115,  116,  London,  March,  1873. 
Abstract  of  same,  with  figure  of  skull  of  Dinoceras  mirahilis. — Nature,  vol.  vii    366 

London,  March  13,  1873. 
Abstract  of  same. — Popular  Science  Review,  p.  213,  London,  April,  1873. 
Abstract  of  same. — Neues  Jahrbuch  fttr  Mineralogie,  etc.,  pp.  334,  335,  Stutto-art,  1875. 


228  DINOCERATA. 

Cope,  Edward  Drinker. — Proceedings  of  the  American  Philosophical  Society,  Vol. 
XII,  number  89,  for  1872,  p.  515.     Philadelphia,  February,  1873. 


Cope,  Edward  Drinker. — On  the  Dentition  of  Metalophodon. — Proceedings  of  the 
American  Philosophical  Society,  Vol.  XII,  number  89,  for  1872,  pp.  542-545. 
PhiladeljAia,  February,  1873. 

The  name  Losolophodon- stated  to  be  a  synonym  of  Bathmodon. 


Marsh,  Othniel  Cliarles. — Communication  on  the  Discovery  of  New  Rocky  Mountain 
Fossils. — Proceedings  of  the  American  Philosophical  Society,  Vol.  XII,  number  89, 
for  1872,  pp.  578,  579.     Philadelphia,  February,  1873. 
A  general  statement  of  the  characters  of  the  Dinocerata. 
The  same. — Annales  des  Sciences  Geologiques,  vol.  iii,  p}).  99,  100,  Paris,  March,  1873. 


Cope,  Edward  Drinker. — On  the  Short  Footed  Ungulata  of  Wyoming. — Proceedings 
of  tlie  American   Philosophical  Society,  Vol.  XIII,  number  90,  for  1873,  pp.  38-74, 
Plates  I-IV.     Philadelphia,  1873. 
The  same,  published  in  advance,  March,  1873. 

Dinocerata  considered  a  suborder  of  Proboscidea,  with  a  list  of  species. 


Cope,  Edward  Drinker. — Observations  on  the  Structure  and  Systematic  Position  of 
the  genus  Eobasileus,  Coidc. — ^Proceedings  of  the  Academy  of  Natural  Sciences,  Vol. 
XXV,  pp.  10-12.     Philadelphia,  March,  1873. 
The  same,  Avith  changes,  published  in  advance,  1873. 
Eobasileuf!  and  allied  genera  referred  to  the  Proboscidea. 


Cope,  Edward  Drinker. — On  the  New  Perissodactyles  from  the  Bridger  Eocene. — 
Proceedings  of  the  American  Philosophical  Society,  Vol.  XIII,  number  90,  for  1873, 
pp.  35,  36.     Philadelphia,  1873. 
The  same,  under  the  title— On  Two  New  Perissodactyles  from  the  Bridger  Eocene. — 
Palaeontological  Bulletin  No.  11.     Philadelphia,  1873. 


Marsh,  Othniel  Charles. — Note  on  the  Dates  of  some  of  Professor  Cope's  recent 
Papers. — American  Journal  of  Science  and  Arts  (3),  Vol.  V,  jip.  235,  236.  New 
Haven,  March,  1873. 

Errors  corrected  in  the  dates  of  the  Philosophical  Society's  meetings  at  which  Prof.  Cope's  papers 
were  claimed  to  have  been  read. 

The  same,  American  Naturalist,  Vol.  VII,  p.  173.     Salem,  March,  1873. 


BIBLIOGRAPHY.  229 

Marsh,  Otliniel  Charles.— The  Fossil  Mammals  of  the  order  Dinocerata.— American 
ISTatui-alist,  Vol.  VII,  pp.  146-153  ;  Plates  I-II.     Salem,  March,  1873. 

Characters  of  the  order  Dinocerata,  with  list  of  errors  in  Prof.  Cope's  papers  on  the  same  subject,  and 
figures  of  skull  oi  Dinoceras  inirahile. 


Cope,  Edward  Drinker.— The  Gigantic  Mammals  of  the  Genus  Eobasileus.— American 
Naturalist,  Vol.  VII,  pp.  157-160.     Salem,  March,  1873. 

Description  of  Eobasileus,  referring  this  form  and  Vintatherium  to  the  Proboscidea. 


Cope,  Edward  Drinker.— Table  of  Genera  of  Short  Footed  Ungulates  of  the  American 
Eocene.^Proceedings  of  the  Academy  of  Natural  Sciences,  Vol.  XXV,  pp.  102,  103. 
•Philadelphia,  March,  1873. 


Cope,    Edward    Drinker.— The  Eobasileus  again.— American  Naturalist,  Vol.  VII,  p^ 
180.     Salem,  March,  1873. 

A  denial  of  errors  charged  in  regard  to  the  Dinocerata. 


Marsh,  Othniel    Charles.— Additional  Observations  on  the  Dinocerata.- American 
Journal  of  Science  and  Arts,  Vol.  V,  pp.  293-296.     New  Haven,  April,  1873. 
The  same,  published  in  advance,  Jlarch  18,  1873. 

A  correction  of  errors  in  Prof.  Cope's  publications,  with  a  list  of  ihe  known  species  of  Dinocerata. 

Abstract  of  same. — Nature,  vol.  vii,  p.  491,  London,  April  24,  1873. 


Marsh,  Othniel  Charles. — Supplementary  Note  on  the  Dinocerata. — American  Journal 
of  Science  and  Arts  (3),  Vol.  V,  pp.  310,  311.     New  Haven,  April,  1873. 
The  same,  published  in  advance,  March  22,  1873. 

Errors  in  Prof.  Cope's  statements  and  plates  pointed  out,  and  names  Loxolophodon  and  Eobasileus 
rejected. 


Marsh,    Othniel    Charles.  — On    the    Genus   Tinoceras    and    its    Allies.— American 
Naturalist,  Vol.  VII,  pp.  217,  218.     Salem,  April,  1873. 

Enumeration  of  errors   in   Prof.  Cope's  recent  papers,  and  remarks  upon  photographs  of  Tinoceras 
cornutum. 


Grarrod,  Alfred  Henry.— On  the  Affinities  of  Dinoceras  and  its  Allies  —Nature,  Vol. 
VII,  p.  481.     London,  April  24,  1873. 

Dinocerata  regarded  as  belonging  to  the  Arliodactyla. 


230  DINOCERATA. 

Cope,    Edward    Drinker.  —  On   some   of   Professor   Marsh's   Criticisms.  —  American 
Naturalist,  Vol.  VII,  pp.  290-299  ;  Plates  IV- V.     Salem,  May,  1873. 
A  denial  of  errors  in  description  of  Eobasileus,  and  in  the  dates  of  publications. 
The  same,  with  additions,  Palseontological  Bulletin,  No.  13.     Philadelphia,  1873. 


Marsh,  Othniel  Charles. — On  the  dates  of  Professor  Cope's  Recent  Publications.- 
American  Naturalist,  Vol.  VII,  pp.  303-306.     Salem,  May,  1873. 
A  protest  against  the  authenticity  of  the  dates  claimed  by  Prof.  Cope. 


Marsh,  Othniel  Charles. — ^Tinoceras  and  its  Allies. — American  Naturalist,  Vol.  VII, 
pp.  306-308.     Salem,  May,  1873. 

Correction  of  errors  contained  in  Prof.  Cope's  recent  papers. 


Cope,    Edward     Drinker. — On    the    Tusk    of    Loxolophodon    cornutus. — American 
Naturalist,  Vol.  VII,  p.  315.     Salem,  May,  1873. 


Marsh,  Othniel  Charles. — Notice  of  New  Tertiary  Mammals. — American  Journal  of 
Science  and  Arts  (3),  Vol.  V,  pp.  407-410.     New  Haven,  May,  1873. 
Definition  of  tlie  genera  Tinoceras  and  Dinoceras,  with  first  description  of  D.  lucare. 
Abstract  of  same. — Najbure,  vol.  viii,  p.  76,  London,  May  22,  1873. 


Marsh,    Othniel    Charles. — Reply    to   Professor     Cope's     Explanation. — American 
Naturalist,  Vol.  VII,  appendix,  pp.  i-ix.     Salem,  June,  1873. 

Statement  in  detail  of  the  errors  and  incorrect  dates  of  Prof.  Cope's  papers  on  the  Dinoceraia. 


Marsh,  Othniel  Charles. — New  Observations  on  the  Dinocerata. — American  Journal 
of  Science  and  Arts  (3),  Vol.  VI,  pp.  300,  301.     New  Haven,  October,  1873. 
Additional  characters  of  the  order,  and  first  description  of  Dinoceras  laticeps. 

The  same,  j^ublished  in  advance,  September,  1873, 


Marsh,  Othniel  Charles. — On  the  Gigantic  Mammals  of  the  American  Eocene. — 
Proceedings  of  the  American  Philosophical  Society,  VoL  XIII,  number  90,  pp.  255, 
256.     Philadelphia,  1873. 


BIBLIOGRAPHY.  2;31 

Leidy,  Joseph.— Contributions  to  tlie  Extinct  Vertebrate  Fauna  of  the  Western 
Territories.— Report  of  the  United  States  Geological  Survey  of  the  Territories, 
F.  V.  Hayden,  4to,  Vol.  I.  Washington,  ISYS.  (Dinocerata,  pp.  93-109,  331-334; 
Plate  XXV;  Plate  XXVI,  figs.  1-8;  Plate  XXVII,  figs.  30-34.) 

A  full  discussion  of  the  structure,  classification,  etc.,  of  tlie  Dinocerata. 

On  page  95  of  this  memoir.  Dr.  Leidy  in  citing  the  descriptiou  of  Dinoceras  mirdbile  inadvertently 
oraiuedthcf  llowing:  "small,  compressed,  osseous  elevations  which  probably  supported  a  pair 
of  horns.  The  maxillaries  have  a  pair  of."  Prof.  Cope,  referring  apparently  not  to  the  original 
paper,  hut  to  this  inomplete  passage,  has  since  asserted  that  the  author  placed  the  posterior 
horn-cores  of  Dinoceras  on  the  frontal  bones,  a  statement  without  foundation. 


Cope,  Edward  Drinkei*.- On  the  Extinct  Vertebrata  of  the   Eocene  of  Wyoming 
observed   by  the  Expedition    of    1872.— United   States    Geological    Survey  of   the 
Territories,  Sixth  Annual  Report,  F.  V.  Hayden,  8vo,  pp.  543-649,  Plates  I-VI. 
Washington,  1873. 

Discussion    of    the   Dinocerata,   with   descriptions    of    this  author's    species,   and  with    figures    of 
Tinoceras  cornutum. 


Cope,  Edward  Drinker.— Palaeontological  Bulletins  Nos.  1-13,  8vo,  Philadelphia,  1873. 
Contains  reproductions,  among  others,  of  the  following  papers,  some  with  additions  or 

corrections,  viz: 
No.  5. — Telegram  from  Black  Buttes,  Wyoming. 
No.  6.— Notices  of  New  Vertebrata  from  the  Upper  Waters  of  Bitter  Creek,  Wyoming 

Territory.     Reprint. 
]Sro.  7.— Second  Notice  of  Extinct  Vertebrates  from  Bitter  Creek,  Wyoming.    Reprint. 
No.  II.— On  two  New  Perissodactyles  from  the  Bridger  Eocene.     With  changes. 
No.  13. — On  some  of  Professor  Marsh's  Criticisms.     With  additions. 


1874. 

Marsh,  Othniel  Charles.— SmaR  Size  of  the  Brain  in  Tertiary  Mammals.— American 
Journal  of  Science  and  Arts  (3),  Vol.  VIII,  pp.  66,  67.     New  Haven,  July,  1874. 

The  same,  published  in  advance,  1874. 

The  same.— American  Naturalist,  vol.  viii,  pp.  503,  504,  Salem,  August,  1874. 

The  same.— Annals  and  Magazine  of  Natural  History  (4),  vol.  xiv,  p.  167,  London, 
August,  1874. 

Abstract  of  same. — Nature,  vol.  x,  p.  273,  London,  August  6,  1874. 

The  same.— Journal  de  Zoologie,  vol.  ill,  pp.  326,  327,  Paris,  1874. 

Abstract  of  same.— Neues  Jahrbuch  fur  Mineralogie,  etc.,  p.  772,  Stuttgart,  1874. 


232  DINOCERATA. 

Cope,   Edward  Drinker. — Report  ou   the  Vertebrate  Palaeontology  of   Colorado. — 
Annual  Report  of  the  United  States   Geological  and  Geographical  Survey  of  the 
Territories  for  1873,  F.  V.  Hayden,  pp.  427-533,  Plates  I— VIII.     Washington,  1874. 
Description  of  EobasUeus  galeatus,  wliich,  on  Plate  I,  is  called  Loxolophodon  galeatus. 


Marsk,  Othniel  Charles. — On  the  Structure  and  Affinities  of  the  Brontotheridae. — 
American  Journal  of  Science  and  Arts  (3),  Vol.  VII,  pp.  81-86,  Plates  I,  II.  New 
Haven,  January,  1874. 

Contains  a  comparison  of  the  brain  in  Brontotherium  and  Dinoceras. 
Abstract  of  the  same. — Nature,  vol.  ix,  p.  227,  London,  January  22,  1 
The  same. — American  Naturalist,  vol.  viii,  pp.  79-85,  Salem,  February,  1874. 
Abstract  of  same. — Journal  de  Zoologie,  vol.  iii,  pp.  61,  62,  Paris,  1874. 


1875. 

Marsh,  Othniel  Charles.— Ancient  Lake  basins  of  the  Rocky  Mountain  Region. — 
American  Journal  of  Science  and  Arts  (3),  Vol.  IX,  pp.  49-52.  New  Haven, 
January,  1875. 

Contains  a  description  of  the  Eocene  Lalje-basin  in  which  the  Dinocerata  are  found. 
Abstract  of  same. — American  Naturalist,  vol.  ix,  p.  119,  Salem,  February,  1875. 
Abstract  of  same. — Geological  Magazine  (2),  vol.  ii,  pp.  232,  233,  London,  May,  1875. 


Cope,  Edward  Drinker. — The  Feet  of  Bathmodon.^Proceedings  of  the  Academy  of 
Natural  Sciences,  Vol.  XXVII,  p.  73.     Philadelphia,  May,  1875. 
The  Dinocerata,  from  the  structure  of  the  feet,  regarded  as  a  suborder. 


1876. 

Marsh,  Othniel  Charles. — -Principal  Characters  of  the  Dinocerata,  Part  I. — American 
Journal  of  Science  and  Arts  (3),  Vol.  XI,  pp.  163-168,  Plates  II-VL  New  Haven, 
February,  1876. 

Discussion   of   the   order  Dinocerata,   with  plates  of  the   skull,   brain-cast,    lower  jaw,  and  feet  of 
Dinoceras. 
Abstract  of  same. — Nature,  vol.  xiii,  p.  374",  London,  March  9,  1876. 
The  same. — Journal  de  Zoologie,  vol.  v,  pj).  136-145,  Paris,  1876. 
Abstract  of  same. — Zeitschrift  fiir  die  gesammten  Naturwissenschaften,  vol.  xiv,  pp. 

31,  32,  Berlin,  1876. 
Abstract  of  same. — Neues  Jahrbuch  fiir  Mineralogie,  etc.,  pp.  780,  781,  Stuttgart,  1876. 
Abstract  of  same. — Popular  Science  Review,  pp.  326,  327,  London,  July,  1876. 


BIBLIOGRAPHY.  233 

Marsh,  Othniel  Charles. — The  Brain  of  Dinoceras. — American  Naturalist,  Vol.  X, 
p.  182.     Boston,  March,  1876. 


Owen,  Richard. — On  the  existence  or  not  of   Horns  in  the  Dinocerata. — American 
Journal  of  Science  and  Arts  (3),  Vol.  XI,  pj).  401-403.     New  Haven,  May,  ISTG. 
Doubts  expressed  as  to  the  presenue  of  true  horns  iu  the  Dinocerata.     (See  page  IST  of  the  present 
volume). 


Marsh,  Othniel  Charles. — On  some  of  the  Characters  of  the  genus  Coryphodon, 
Owen. — -American  Journal  of  Science  and  Arts  (3),  Vol.  XI,  pp.  425-428.  New 
Haven,  May,  1876. 

A  comparison  of  the  brain-oast  in  Coryphodon  and  Dinoceras. 

Abstract  of  same. — Popular  Science  Review,  p.  327,  London,  July,  1876. 
Abstract  of  same. — Neues  Jahrbuch  ftir  Mineralogie,  etc.,  p.  781,  Stuttgart,  1876. 
Abstract  of  same. — Bibliotheque  TJniverselle.      Archives  des  Sciences  Physiques  et 
NaturelLes,  vol.  Ivi,  pp.  273,  274,  Geneva,  1876. 

Flower,    William    Henry.— On  the  Extinct   Animals    of   North   America. — Popular 

Science  Review,  Vol.  XV,  pp.  276-298,  Plate  CXXXVIII.     London,  July,  1876. 

Contains  a  brief  dfiscription  of  the  Dinocerata,,  with  figures  of  sliuU  and  hind  feet  of  Dinoceras. 


Marsh,    Othniel     Charles. — Recent    Discoveries     of     Extinct    Animals. — American 
Journal  of   Science  and  Arts   (3),  Vol.  XII,  pp.  59-61.     Nov  Haven,  July,  187G. 
The  same,  American  Naturalist,  Vol.  X,  pp.  436-439.     Boston,  July,  1876. 
Abstract  of  same. — Neues  Jahrbuch  fur  Mineralogie,  etc.,  p.  782,  Stuttgart,  1876. 


1877. 

[Cope,    Edward   Drinker.] — The   Lowest  Mammalian  Brain. — American    Naturalist, 
Vol.  XI,  pp.  312    313.     Boston,  May,  1877. 


Marsh,    Othniel   Charles.— Brain  of    Coryphodon. — American   Naturalist,  Vol.   XI, 
p.  375.     Boston,  Jvme,  1877. 
Abstract  of  same.— Nature,  vol.  xvii,  p.  340,  London,  February  28,  1878 

Cope,    Edward    Drinker.— Brain    of    Coryphodon. — Proceedings   of    the   American 
Philosophical  Society,  Vol.  XVI,  pp.  616-620,  Plates  I,  IL     Philadelphia,  1877. 
Contains  a  comparison  of  brain-casts  in  Coryphodon  and  Dinoceras. 


234  DINOCERATA. 

Marshy  Othniel  Charles. — Principal  Characters  of  the  Coryphodontidse. — American 
Journal  of  Science  and  Arts  (3),  Vol.  XIV,  pp.  81-85,  Plate  IV.  New  Haven,  July, 
1811. 

A  comparison  of  Coryphodon  and  Oinoceras,  with  figures  of  the  feet  in  both. 

The  same. — Journal  de  Zoologie,  vol.  vi,  pp.  380-385,  Paris,  1877. 

Abstract  of  same. — American  Naturalist,  vol.  xi,  p.  500,  Boston,  August,  1877. 

Abstract  of  same. — Neues  Jahrbuch  ftir  Mineralogie,  etc.,  p.  767,  Stuttgart,  1877. 


Cope,  Edward  Drinker. — Report  upon  the  Extinct  Vertebrata  obtained  in  New 
Mexico  by  Parties  of  the  Expedition  of  1874. — United  States  Geographical  Surveys 
West  of  the  100th  Meridian,  Wheeler,  Vol.  IV,  Palaeontology,  Part  II,  pp.  179-186, 
273,  282.     Washington,  1877. 

Dinocerata  here  considered  a  suborder  of  the  Amblypoda. 


Marsh.,  Othniel  Charles. — -Introduction  and  Succession  of  Vertebrate  Life  in 
America. — .A.n  Address  delivered  before  the  American  Association  for  the 
Advancement  of  Science,  at  Nashville,  Tenn.,  August  30,  1877.  Proceedings,  Vol. 
XXVI,  I3p.  211-258,  Salem,  1878. 

Contains  a  reference  to  the  characters  and  affinities  of  the  Dinocerata. 

The  same  published  in  advance,  pp.  1-57.     8vo.     New  Haven,  August,  1877. 

The  same. — Nature,  vol.  xvi,  j^p.  448-450,  470-472,  and  489-491,  London,  September 

20,  27,  and  October  4,  1877. 
The    same. — American   Journal  of  Science  (3),    vol.    xiv,    pp.  337,  378,  New  Haven, 

November,  1877. 
The  same  with  jjlate. — Popular  Science  Monthly,  vol.  xii,  pp.  511-527  and  672-697, 

New  York,  March  and  April,  1878. 
The  same. — Revue   Scientifique  de  la  France  et  de  V  Etranger  (2),  vol.  vii,  pp.  1039- 

1046,  and  1064-1074,  Paris,  May  4  and  11,  1878. 


1878. 

Gaudry,  Albert. — Les  Enchainments  du  Monde  Animal  dans  les  temps  Geologiques. 
Mammif^res  Tertiares,  8vo,  pp.  1-293,  figure  86.     Paris,  1878. 


Marsh,   Othniel  Charles. — T'inoceras. — Johnson's  New  Universal  Cyclopedia,  Vol. 
IV,  pp.  808,  869.     New  York,  1878. 


King,    Clarence. — United   States    Geological   and    Geographical   Exploration   of  the 
Fortieth  Parallel,  Vol.  I,  Systematic  Geology,  p.  403.     4to.     Washington,  1878. 
A  partial  list  of  the  species  of  Dinocerata  occurring  in  the  Bridger  beds  of  the  Eocene. 


BIBLIOGRAPHY.  235 

Osboru,    Henry    Fairfield;    Scott,    William    Berryman;    Speir,    Francis  — 

Palseontological  Report  of  the  Princeton  Scientific  Expedition  of  187Y;  Contributions 
from  the  Museum  of  Geology  and  Archaeology  of  Princeton  College,  No.  1,  8vo, 
pp.  146,  Plate  A,  and  I-X.     New  York,  ISVS. 

Contains  (pp.  62-82,  Plates  YI,  Til)  first  descriptions  of  Uintatherium  Leidianum  and  U.  princeps, 
with  figures. 

Ryder,  John    A.— On  the  Mechanical  Genesis  of  Tooth  Forms.— Proceedings  of  the 
Academy  of  Natural  Sciences  for  1878,  pp.  45-80.     Philadelphia,  April,  1878. 


1879. 

Osborn,  Henry  Fairfield,  and  Speir,  Francis.— The  Lower  Jaw  of  Loxolophodon.— 
American  Journal  of  Science  and  Arts  (3),  Vol.  XVII,  pp.  304-309,  Plate  I.  New 
Haven,  April,  1879. 

Description  of  the  lower  jaw  of  a  female  Tinoceras,  or  allied  genus. 

Nicholson,  Alleyne.— Manual  of  Palaeontology,  8vo,  Vol.  II,  p.  370-373,  figs.  656,  657. 
Edinburgh  and  London,  1879. 

Description  of  the  Dirwcerata,  with  figures  of  the  skull  and  feet  of  Binoceras  miraUle,  from  the 
present  volume. 

1880. 

Dana,  James  Dwight.— Manual  of  Geology,  Third  Edition,  8vo,  pp.  604,  508,  Plate 
VH,  figs.  1-4;  Plate  XI,  fig.  1.     New  York,  1880. 

A  reference  to  the  Dinoceraia,  with  figures  from  the  present  memoir. 


1881. 

Cope,  Edward  Drinker.— On  the  Vertebrata  of  the  Wind  River  Eocene  Beds  of 
Wyoming. — Bulletin  of  the  United  States  Geological  Survey,  F.  V.  Hayden,  Vol. 
VI,  pp.  183-202.     Washington,  February,  1881. 

Contains  (pp.  194-196)  first  description  of  Uintatherium  Jksidens. 

Garrod,  Alfred  Henry. — Dinocerata. — Journal  of  Anatomy  and  Physiology,  VII,  pp. 
267-270.     London  and  Cambridge,  June,  1873. 
The  same.  Complete  Writings,  edited  by  W.  A.  Forbes,  8vo,  pj).  121-123.     London, 
1881. 

Opinion  that  the  Binocerala  belong  to  a  family  of  the  Artiodactyla. 

Marsh,  Othniel  Charles. — Restoration  of  Binoceras  mirahile. — American  Journal  of 
Science  (3),  Vol.  XXH,  pp.  31,  32,  Plate  II.     New  Haven,  July,  1881. 
The  same,  published  in  advance,  June  14,  1881. 

First  restoration  of  Dinoceras  mirahik,  new  characters  in  the  skull  and  sternum,  and   distinction 
stated  between  this  genus  and  Uintathmum. 

Abstract  of  same. — Archives  des  Sciences  Physiques  et  Naturelles,  vol.  vi,  pp.  323,  324 
Geneva,  September,  1881. 


236  DINOCERATA. 

Osborn,  Henry  Fairfield. — A  Memoir  upon  Loxolophodon  and  TJintatlierium  (Two 
Genera  of  the  Sub-Order  Dinocerata). — Contributions  from  the  E.  M.  Museum  of 
Geology  and  Archaeology  of  the  College  of  New  Jersey,  Vol.  I,  No.  1,  4to,  pp.  54, 
Plates  I-I Y.     Pr inceton ,  1 8  8 1 . 

A  general  discussion  of  the  Bmocerata,  and  first  description  of  Tinocera,s  Speirianum,  witb.  a  restoration. 
The  statement  on  page  17  in  regard  to  the  discover}'  of  the  Dinocerata  is  erroneous,  as  the  author 

was  nearly  two  years  earlier  in  the  field  than  is  there  implied.      See  Introduction,  page  2,  of 

the  present  volume. 


1882. 

Cope,  Edward  Drinker. — Contributions  to  the  History  of  the  Vertebrata  of  the 
Lower  Eocene  of  Wyoming  and  New  Mexico,  made  during  18S]. — Proceedings  of 
the  American  Philosophical  Society,  number  111,  for  1882,  pp.  ISO-lD'?.  Philadel- 
phia, 1882. 

[Cope,  Edward  Drinker.] — American  Naturalist,  Vol.  XVI,  plate  XVIT,  p.  1029. 
Philadelphia,  December,  1882  ;  Vol.  XVII,  Erratum. 

A  restoration  of  Tinoceras  cornutum,  without  text. 

LeConte,  Joseph. — Elements  of  Geology,  Second  Edition,  pp.  525,  526,  figs.  845,  845a, 
8vo.     New  York,  1882. 

A  brief  description  of  Dinoceras  and  Tinoceras,  with  figures  from  the  present  volume. 

Tomes,  Charles  Sissmore. — Dental  Anatomy,  Human  and  Comparative,  Svo,  pp.  440. 
Second  Edition,  London,  1882.     \_Dinocerata,  pp.  340-342,  figure  146.] 


1883. 

Cope,  Edward  Drinker. — On  Uintatherium  and  Bathmodon. — American  Naturalist, 
Vol.  XVII,  p.  68.     Philadelphia,  January,  1883. 

Cope,  Edward  Drinker. — On  Uintatherium,  Bathmodon  and  Triisodon. — Proceedings 
of  the  Academy  of  Natural  Sciences  for  1882,  pp.  294-300.  Philadelphia,  January, 
1883. 

Cope,  Edward  Drinker. — The  Classification  of  the  Ungulate  Mammalia. — Proceedings 
of  the  American  Philosophical  Society  for  1882.  Vol.  XX,  pp.  438-447.  Philadel- 
phia, 1883. 

Flower,  William  Henry. — Mammalia. — Encyclopaedia  Britannica,  9th  Edition,  Vol. 
XV,  p.  426,  fig.  105  (from  present  volume).     Edinburgh,  1883. 

Wortman,  Jacob  L. — The  Carpal  bones  of  the  Dinocerata. — Science,  Vol.  I,  p.  151. 
Cambridge,  March  9,  1883. 


BIBLIOGRAPHY.  237 

1884. 

Marsh,  Othniel  Charles. — The  Gigantic  Mammals  of  the  Order  Dinocerata.  Fifth 
Annual  Report  of  the  United  States  Geological  Survey,  8vo,  pp.  245-302,  figs. 
36-137.     Washington,  1884. 

Ad  extended  abstract  of  the  present  volume,  with  102  illustrations. 

Cope,  Edward  Drinker.— The  Amblypoda. — American  Naturalist,  Vol.  XVIII,  pp. 
1110-1121,  figs.  7,  8,  10.     Philadelphia,  November,  1884, 
Contains  figures  of  the  lower  jaw  of  Uiniatherium  fissidens. 


POSTSCRIPT. 

The  Plates  of  the  present  volume,  with  their  accompanying  pages  of 
explanations,  were  nearly  all  printed  in  1881  and  1882,  and  the  last  of  the 
series,  in  February,  1883.  Most  of  the  other  illustrations,  also,  were 
completed  by  the  latter  date.  In  consequence  of  an  unexpected  delay  in 
printing  the  text,  some  of  the  figures  prepared  for  the  Monograph  first 
appeared  elsewhere. 

An  extended  abstract  of  this  volume,  with  102  illustrations,  was 
prepared  by  the  author,  in  July,  1884,  for  the  Fifth  Annual  Report  of  the 
Director  of  the  United  States  Geological  Survey,  and  references  to  the 
pages  of  this  Report  will  be  found  in  the  preceding  Synopsis. 

With  the  permission  of  the  Director  of  the  United  States  Geological 
Survey,  an  author's  edition  of  500  copies  of  this  work  was  printed  in  Feb- 
ruary, 1885. 


INDEX. 


A. 

Page. 

Amblydadty la ,  characters  of  the 176 

Amia,  occurrence  of,  with  Dinocerata  remains 9 

Anaynodon  ads'cnus,  xiew  of  skull  of    04 

Anterior  dorsal  ribs,  description  of  the  130-132 

Artiodactyla,  comparison  of,  with  Diuoceiata 181 

■     development  of  foot  in 188,189 

Astragalus,    views    and    description    of    the    (PI. 

XLVII) 146-151 

Atlas,  views  and  description  of  the  (PI.  XX) 69-71 

Auchenia  vicugna,  view  of  skull  of 67 

Axis,  views  and  description  of  the  (PI.  XXI) 72,  73 

E. 

Baptanodon  discus,  view  of  left  hind  limb  of   183 

Baur,  G.,  acknowledgment  of  aid  of xviii 

B.bliography  of  Dinocerata 225-237 

Brain,  description  of  the 53-67 

Brain-cast,  views  and  description  of  tbe  (PL  VI)...  53-55 

Brain-growth,  description  of 57-67 

Brain-growth  in  mammals,  laws  regulating 58-60 

Bridger  series 6 

Brontotberium  beds,  situation  of  the 6 

Brontotherium  ingens,  view  of  skull  of 61 

view  of  right  feet  of 180 

C. 
Calcaneum,    views    and    description    of    the    (PI. 

XLViri) 151-153 

Canines,  di  scriplion  of  the 43-^6 

Capra  hircus,  view  t'f  left  feet  of 188 

Carpal  bones,  description  of  the loi 

Carter,  J.  V.  A.,  collection  of  specimens  by 196,  219 

Caudal  veitebrse,  views  and  description  of  the  (PL 

XLIII) 138 

Cervical    vertebrte,   views  and  description   of  the 

(PL  XXII) 09-78 

Cei  vua  Virginianas,  view  of  skull  of 67 

Chelydra  serpentina,  view  of  right  fore  footof 183 

Cheney,  H.  G.,  collection  of  specimens  by 195 

Chew,  J.  W.,  collection  of  specimens  by 194,195,196, 198. 

201,  202,  203,  208,  210,  213,  221,  222 

Clinrdactyla,  characters  of  the 175 

Colon<iceraa,  occurrence  of,  with  Dinocerata  remains  9 

Colonoceras  agrestis,  view  of  skull  of 64 

Conclusions  169-191 

Cope,  E.  D.,  Dinocerata  collections  of 4,5 

CDllection  of  specimens  by 2O8, 209 

publications  of,  n-spcctin^^  Dinocerata  226-237 

Coryphodou,   dentition  of,  contrasted  with  that  of 

Dinocerata : 51 

Coryphodon  and  Dinocerata,  comparison  of  astraga- 
lus in  148 

Coryphodon  beds    5  G 


Page. 

Coryphodon  hamatus,  views  of  molar  series  of 52 

view  of  skull  of 63 

views  of  left  feet  of 184 

Coryphodontia  and  Dinocerata,  characters  in  com- 
mon of  the 179 

Corson,  J.  K.,  colled  ion  of  specimens  by 219 

Crjini;il  nerves,  description  of  the 55-57 

Cuboid,  viewsand  desciiptionof  the  (PI.  XLIX)...  153-155 
Cnneifurm.     See  Pyramidal. 

D. 

Dana,  J.  D.,  references  to  Dinocerata  in  publica- 
tions of 235 

Dicot.>  Ics  torquatus,  view  of  skull  of 67 

Dinoceias,  place  of,  among  Dinocerata 10 

variation  of  premaxillaries  in 24 

dentition  of. 41 

biain  of 56 

measurements  of  first  metacarpal  of 121 

measurements  ot  fourth  metacarpal  of 120 

characters  of  the  genus 191 

list  of  species  of,  with  account  of  specimens 194-202 

Dinoceras  agreste,  view  of  skull  of 19 

description  of  ucciput  of 20 

description  of  specimens  of 197 

Dinoceras  and  Mastodon  Americanus,  comparison 

of  pelvic  arch  in 137 

Dinoceras  and  Tinoceras,  restorations  of 165-168 

Dinoceras  beds,  sit  nation  of 3, 6 

Dinoceras  cuneum,  views  and  description  of  sixth 

cervical  vertebra  of 77 

measurements  of  sixth  cervical  vertebra  of 78 

description  of  specimens  of 197, 198 

Dinoceras  diaians,  view  of  nasals  of 13 

view  of  skull  of 15, 16,  29 

description  of  specimens  of 199 

Dinoceras  laticeps,  view  of  skull  of 19,  26,  30, 54 

descriptionof  occiput  of 20 

view  of  palate  of 25 

views  and  descriptions  of  skull  of  (PI.  X,  XI, 

XIV) 26,45 

views  and  descriptions  of  lower  jaw  of  (PI.  XII, 

Xni) 35,36 

measurements  of  lower  jaw  of 40 

view  of  upper  canine  of 43, 44 

view  and  measurements  of  left  scaphoid  of 103 

views  and  descriptions  of  caudal  veriebrEe  of  (PI. 

XLIH) 138 

views  of  left  astragalus  of 149 

measurements  of  left  astragalus  of 150 

measurements  of  left  ectocuneiforra  of 160 

descripl  ion  of  specimens  of 200 

Dinoceras  lucare,  maxillary  bone  in 28 

views  and  descriptions  of  teeth  of  (PL  IX)   43, 45, 49 

239 


240 


INDEX. 


Dinoceras  lucare — Continued. 

■meaauiement  nf  axis  of '3 

views  of  posterior  dorsal  veretebra  of 84 

measurements  and  views  of  section  of  ulna  of. . .  98,  99 

measurements  of  fourth  metacarpal  of 126 

description  of  specimens  of 200,201 

Dinoceras  mirabile,  views  and  descriptions  of  skull 

of  (PI.  I-V)  11. 24 

view  of  nasals  of 13 

view  of  skull  of 15,19,26,31,32.61 

tIbws  of  lower  jaw  of 38 

views  of  incisors  of ^2 

views   and   descriptions  of   teeth   of    (PI.    "Vn, 

YjH) 46,  48,  49,  50 

views  and  descriptions  of  brain-cast  of  (PI.  VI) . .  53-55 

views  and  description  of  atlas  of  (PI.  XX) 69 

measurements  of  atlas  of 71 

views  and  description  of  axis  of  (PL  XXI) 72 

measurements  of  axis  of 73 

description  and  measurements  of  third  cervical 

vertebra  of 74 

views  and  descriptions  of  cervical  vertebrse  of 

(PL  XXII) 74.78 

measurements  of  fourth  cervical  vertebra  of 75 

views  and  measurements  of  fifth  cervical  verte- 
bra of 76 

views  and  description,  of  sixth  cervical  vertebra 


of. 


77 


description  and  measurements  of  seventh  cervi- 
cal vertebra  of 

measurements  of  sixth  cervical  vertebra  of  ..-.- 
description  and  views  of  first  dorsal  vertebra  of     79,1 

raeasureraentsof  first  dorsal  vertebra  of '• 

description  and  views  of  second  dorsal  vertebra 


of. 


views  and  descriptions  of  dorsal  vertebrse  of  (PL 

XXIII,  XXIV) 82,  84 

measurements  of  second  dorsal  vertebra  of 83 

views  and  descriptions  of  lumbar  vertebrae  of 

(PL  XXV,  XXVI) 85 

measurements  of  four  lumbar  vertebrse  of 86 

views  and  descriptions  of  left  scapula  of  (PL 

XXVII) 87 

measurements  of  left  scapula  of 88 

views    and    description    of    humerus    of    (PL 

S  XVin) 89 

measurements  and  views  of  section  of  humerusof  91,  92 

views  and  descriptions  of  radius  of  (PL  XXIX) .  93.  94 

measurements  of  section  of  radius  of 95 

views  and  descriptions  of  ulna  of  (PL  XXX).  - . .  96 

measurements  and  views  of  section  of  ulna  of. . .  98,  99 

views  and  descriptions  of  feet  of  (PL  LIV) 101, 145 

views  and  descriptions  of  scaphoid  and  lunar  of 

(PLXXXI) 102,104 

view  of  right  and  measurements  of  right  and 

left  scaphoid  of 103 

view  of  right  lunar  of 105 

measurements  of  right  lunar  of 106 

views  and  descriptions  of  pyramidal  and  pisiform 

of  (PL  XSXII) v..  107,109 

view  and  measurements  of  left  pyramidal  of 108 

measurements  of  right  pisiform  of 110 

views  and  descriptions  of  trapezium  and  trape- 
zoid of  (PL  xxxiH) 110,111 

measurements  of  left  trapezium  of Ill 


Page. 
Dinoceras  mirabile  —  Continued. 

views  and  measurements  of  left  trapezoid  of 112, 113 

views  and  descriptionp  of  magnum  and  unciform 

of  (PL  XXXIV) 113,115,116.117.119,120 

measurements  of  first  metacai-pal  of 121 

views  and  depcriplions  of  metacarpals  of  (PL 

XXXV-XXXVII) 121, 122, 123, 124, 127 

views    and   descriptions    of   phalanges  of    (PL 

XXXVin.LIlI) 121,127,128,164 

measurem£nts  of  second  metacarpal  of 122 

measurements  of  third  metacarpal  of 124 

measurements  cf  lourth  metacarpal  of 125 

views  and  descriptions  of  ribs  of  (PL  XXXIX) .  129, 133 

views  of  anterior  rib  of 131 

measurements  of  first  anterior  and  median  ribs 

of 132 

measurements  of  dorsal  and  x>osterior  ribs  of  . ..  133 

views  and  descriptions  of  sternum  of  (PL  XL) . .  133, 134 
views  and  desciiptions  of  pelvis  of  (PL  XLI, 

XLn)  135,137 

measurements  of  pelvis  of 137 

views  and  descriptions  of  femur  of  {PL  XLIV) . .         139 
measurements  of  right  femur  and  views  of  sec- 
tion of  femur  of I'll 

views  and  descriptions  of  tibia  of  (PL  XLV) ....  141 

measurements  of  tibia  of 142 

measurements  of  fibula  of 143 

views  and  descriptions  of  fibula  and  patella  of 

(PL  XLVI) 143 

views   and   descriptions   of  astragalus  of  (PL 

XLVn) 146 

measurements  of  right  and  left  astragalus  of 150, 151 

views    and    descriptions  of  calcaneum  of  (PL 

XLVIH) 151, 152 

measurements  of  right  and  left  calcaneum  of —  153 

views  and  descriptions  of  cuboid  and  navicular 

of  (PL  XLIX) 153,155 

views  of  right  and  measurements  of  right  and 

leftcuboidof 154,155 

measuremeuts  of  Itft  navicular  of 157 

views  and  descriptions  of  tarsal  bones  of  (PL  L) .  158, 159 

measurementfi  of  left  mesocuneiform  of 159 

measurements  ofright  and  left  ectocuneiform  of.  160, 161 
views  and  descriptions  of  metatarsals  of  (PL  LI, 

LU) -161,162,163 

view  and  description  of  restoration  of  (PL  LV)..  165 

size  and  appearance  of 165, 166, 168 

views  of  left  feet  of 184 

account  of  specimens  of 194-196 

Dinoceras  reflexura,  description  of  specimen  of 201, 202 

Dinocerata,  discoveries  of  remains  of 2-4 

localities  in  which  remains  of,  have  been  found. .  8 

fossils  fuund  associated  with 9 

place  of,  among  Ungulata 9, 10 

genera  and  species  of 10 

detailed  description  of  skuU  of 11-33 

detailed  description  of  lower  jaw  of 35-40 

detailed  description  of  teeth  of 41-52 

detailed  descri  ption  of  brain  of 53-67 

detailed  description  of  cervical  vertebrse  of 69-78 

description  of  the  dorso-lumbar  vertebrae  of 79-86 

detailed  description  of  fore  limbs  of 87-128 

detailed  description  of  fore  feet  of 101-128 

detail*  d  description  of  ribs  aud  sternum  of 129-134 

detailed  desciiption  of  pelvic  arch  and  tail  of. ..  135-138 


INDEX. 


241 


Page. 

Dinocerata — Cnntinned, 

detailed  description  of  bind  limhs  of 139-1G4 

detailed  description  of  hind  feet  of 145-1 G4 

horn-cores  of 168 

characters  of 178-181 

contrast  of,  with  living  forms 17I)-1?1 

classification  of 10i>,  101 

list  of  species  of,  with  account  of  specimens 193-223 

bibliography  of 225-237 

Diplacodon  beds,  place  of 6 

Dorsal  vertebrae,  views  of  the  (PI.  XXm,  XXIV) . .       82-84 
-  Dorso  lumhai-  rei  tebraa,  description  of  the    79-86 

Di'omocyon.  occurrence  of,  with  Dinocerata  remains.  9 

E. 

EciocuneiCorm,  description  of  the 159-161 

Elcphas  Indicus,  view  of  stull  of 66 

views  of  left  leet  of 185 

Elutherium  crassum.  view  of  skull  of 65 

.Ebtocuueiform,  description  of  the 158 

Eporeodon  socialis,  view  of  skull  of 64 

view  of  left  feet  of 187 

Equus  caballus,  view  of  skull  of 61 

view  of  left  feet  of iS8 

F. 

Femur,  views  and  descriptiona  of  tlie  (PI.  XLIV) ...  139 
measurements  of  right  and  views  of  section  of 

the 141 

Fibula  and  patella,  views  and  description  of  the  (PI. 

XLVI) 143 

Fifth  metacarpal,  description  of  the 127 

Fifth  metatarsal,  description  of  the 163, 164 

Fifth  vertebra,  description  of  the 76 

First  dorsal  vertebra,  dfscription  of  the 79-81 

First  metacarpal,  description  of  the 121 

First  metatarsal,  description  of  the 161 

First  rib,  descriptions  of  the 129 

Flower,  W.  H.,  publications  of,  respecting  Dino- 
cerata    233,  236 

Forearm,  description  of  the 92,  93 

Forefeet,  views  of  the  (PhLIV) ICl 

Fore  limbs,  description  of  the 87-128 

Fourth  metacarpal,  description  of  the 124-126 

Fourth  metatarsal,  description  of  the 163 

Fourth  vertebra,  description  of  the 74,  75 

Frontal  bones,  description  of  the 16-18 

G. 

Garrod,  A.  H.,  publications  of,  respecting  Dino- 
cerata    229,  235 

Gaudry,  Albert,  publications  of,  respecting  Dino- 
cerata    234 

Green  River,  DiDOcerata  remains  from  vicinity  of. ..  8 

Green  River  series 6 

H. 

Hargar,  Oscar,  acknowledgment  of  aid  of xvni 

collection  of  specimens  by 195 

Heisev,  J.,  collection  of  specimens  by 196, 198, 205,  206,  215 

Helaletes,  occurrence  of,  with  Dinocerata  remains  . .  9 

Helioblitia  bcd^  sitnat  ion  of 6 

Hmd  feet,  views  of  the  (Pl.LIV) 145 

Hind  limbs,  description  of  the 139-1 G4 

Hippopotamus  amjjhibius,  view  of  palate  of 25 

vinwof  skull  of 67 

view  of  left   eit  of  187 


Holodactyla,  characters  of 172 

Humerus,  views  of  the  (PI-  XXVUI) 89 

description  of  the 89-92 

Hyopsodus,  occurrence  of,  with  Dinocerata  remains.  9 

Hyrachyns,  occurrence  of,  with  Dinocerata  remains.  9 

Hyrachyus  Rairdianus,  view  of  skull  of 64 

Hyijicoidea,  characters  of 173, 174 

Hyiax  capensis,  views  of  left  feet  of 185 

I. 

Incisors,  descriptiou  of  the 41-43 

-J. 
Jurassic  and  Triassic  mammals,  studies  of  the,  by  0. 

C.  Marsh  169 


King,  Clarence,  list  of  Dinocerata  published  by  . 


Lachrymal  bones,  description  of  the 22 

Lamotte,  L.,  collection  of  specimens  by .  .196, 197,  200,  203,  208, 

211,212,214 

Lane,  E.  S.,  collection  of  specimens  by 195 

Le  Conte,  Joseph,  references  to  Dinocerata  in  publi- 
cations of 236 

Leidy ,  Joseph ,  Dinocerata  collections  of 4 

publications  of,  respecting  Dinocerata 225,  227, 231 

Lemuravus,  occurrence  of,  with  Dinocerata  remains.  9 
Lepidnsteus,    occurrence    of,   with    Dinocerata   re- 
mains   9 

Limnocyon,  occurrence  of,  with  Dinocerata  remains.  9 

Limnofelis,  occurrence  of.  with  Dinocerata  remains.  9 

Limnohyus,  occurrence  of,  with  Dinocerata  remains.  9 

Limnohyus  robustus,  view  of  skull  of 63 

Lower  Eocene,  mammals  of  the    —  189 

Lower  .iaw,  views  of  the  (PI.  YIU,  XLt,  XIH,  XLX) .       35, 49 

descrii)tion  of  the 35-40 

Lower  molars,  description  of  the 50-52 

Lower  premolars,  description  of  the 49,  50 

Lumbar  vertebrae,  views  of  the  (PI.  XXV,  XXVI) . .  85 

description  of  the 85,80 

Lunar,  description  of  the 104-100 

Lunarandscaphoid,  views  of  the  (PI.  XXXI) 102-104 

II. 

Magnum,  description  of  the 113-110 

Magnum  and  unciform,  views  of  the  (PI.  XXXIV)  .  113-117 

Malar  bones,  description  of  the 22 

Marsh,  O.  C,  study  of  Jurassic  and  Triassic  mam- 
mals by   169 

collection  of  .specimens  by 104, 195, 198,  200,  201 ,  214 

publications  of,  respecting  Dinocerata 225-237 

Mastodon  Ameiicanus,  view  of  skull  of 65 

Mastodon  Aroericanus  and  Dinoceras,  comparison 

of  pelvic  arch  in 137 

Maxillaries,  description  of  the 23 

Median  and  posterior  vertebrce,  description  of  the..  84 

Mesoruneiform,  description  of  the 158, 159 

Metacarpal  bones,  views  and  description  of  the  (PI. 

XXXV-XXXVII) 120-127 

Metatai-sal  bones,  views  and  description  of  the  (PI. 

I.I,  LH) 101-164 

Middle  Eocene,  mammals  of  the 189,100 

Arioccne.  mammals  of  the 190 

Miobippus  series,  situation  of  the 6 

Molars,  views  of  the  (Pl.VII.Vm) 46,48,50 


242 


INDEX. 


Page. 

Nasfil  bones,  tlescription  of  the 12-14 

Naviculai-,  viewa  and  description  of  the  (PL  XLIX).  155-157 
Nicholson,  Alley  no,  publications  of,  respecting  Dino- 

cerata 235 

O. 

Oaks,  H.  A.,  collection  of  specimens  by    195 

Occiput,  description  of  the 19-21 

Odontormtht-s,  nidnograph  on xvii 

Oieocyon,  oocmience  of,  with  Dinocerala  remains  ..  9 

Oreodon  bedn,  situation  of  1  he 6 

Oiobippus,  occurrence  of,  with  Dinocerata  remains  .  9 
Osborn,  H.  F.,  publications  of,  respecting  Dinocer- 
ata  235,236 

Owen,  Kichard,  publications  of.  respecting  Dinocer- 
ata   233 

P. 

PalEeosyops,  occuixence  of,  with  Dinocerata  remains.  9 

Palieosyops  laticeps.  view  of  skull  of 63 

Palate,  description  of  the 24-28 

Palatine  bones,  description  of  the 28 

Paleontology,  need  of  illustrations  in xvii 

Parietal  bones,  desci  iption  of  the    18 

Patella  and  fibula,  views  and  description  of  the  (PL 

SLVI)   143 

Pearson,  S.,  collection  of  specimens  by 195,  214,218 

Pelvic  arch  and  tail,  description  of  the 135-138 

Pelvis,  views  and  description  of  the  (PL  XLI,  XLII) .  135-138 

Perisf^odactyls,  comparison  of,  with  Dinocerata 181 

Peiinian  age,  characters  of  mammalia  in  the. 170 

Phalanges,    views    and    description     of    the     (PL 

SXXVIII,  Lin) 127,1-28,164 

Pisiform,  views  and  description  of  the  (PL  XXXH) .  109, 110 

Platysonus  compressus,  view  of  skull  of 65 

Posterior  ribs,  description  of  the 133 

Premaxillarics,  description  of  the... 23,24 

Prenasitl  bones,  description  of  the 14, 15 

Proboscidea  and  Dinocerata,  characters  in  common 

of 179,180 

Proboscidians,  chaiacters  of 174,175 

Protungulata,  characters  of 171 

Pterygoid  bones,  description  of  the 29-31 

Pyramidal  and  pisiform,  views  and  description  of 

the  (PL  XXXrC) 107-110 

K. 

Radius,  views  and  description  of  the  (PL  XXIX) . . .  93-95 

Hestorations,  views  of  the  (Pl.LV.LVI) 165-168 

Ebinoceros  bicornis,  view  of  left  feet  of 186 

Rhinoceros  Sumatrensis,  view  of  skull  of 66 

Ribs  and  sternum,  views  and  description  of  the  (PL 

XXXIX)             129-134 

Ryder,  J.  A.,  publications  of,  respecting  Dinocerata.  235 

~  S. 

Sauranodon,  characters  of  limbs  of 182 

Saiiropoda,  monograph  on xviii 

Scaphoid  and  lunar,  views  and  description  of  the  (PL 

XXXI) 102,103 

Scapula,  views  and  description  of  the  (PI.  XXVH).      87,  88 

Schlosser,  M.,  acknowledgment  of  aid  of xviii 

Scott,  "W.  B.,  publications  of,  respecting  Dinocerata.  235 

Second  dorsal  vertebra,  description  of  the £2,  83 

Second  metacarpal,  description  of  the 122 

Second  metatarsal,  description  of  the 161, 162 


Seventh  vertebra,  description  of  the 78 

Sheridan,  P.  H.,  acknowledgment  of  assistance  by. ..       xviii 
Sherman,  W.  T..  acknowledgment  of  assistance  by. .       xvm 

Shoshone  John,  collection  of  .'specimens  by 196 

Sixth  vertebra,  description  of  the 77,  78 

Skull,  views  and  description  of  the  (PI.  I-V,  X.  XI, 

XIV-XVII) 11-33 

Smith.  B.D.,  colUction  of  specimens  by 194,  195, 196,201, 

210.213 

Smith.  S.,  collection  of  specinien:s  by. . .  .195,  196,198,199,202, 

208,211,214,216,218,222 

Speir,  Francis,  colli  ciion  of  specimens  by 216 

publications  of,  respecting  Dinocerata ir35 

Squamosal  bones,  description  of  the 22 

Stegosauria,  monograph  on xvm 

Sternum,  views  and  description  of  the  (PL  XL) 133, 134 

Stylinodon,  occurrence  of,  with  Dinocerata  remains.  9 

Synopsis  of  Dinocerata 193-2^:3 

T, 
Tapirus  terrestris,  view  of  skull  of 66 

Tarsal  bones,  views  and  description  of  the  (PI. L)..  145 

Teeth,  views  and  description  of  the  (PI.  VII-IX, 

xvnr,  XIX) 41-52 

Tertiary,    divisions    of,    in    Europe    and    Western 

America 5-8 

Tertiary  age,  law  of  brain-growth  in  extinct  mam- 
mals of  the 58 

development  of  mammalian  life  in  the 189,190 

cause  of  disappearance  of  mammals  of  the 190 

Third  dorsal  vertebra,  description  of  the 83 

Third  metacarpal,  description  of  the 123,124 

Third  metatarsal,  desciiption  of  the...  162,163 

Third  vertebra,  description  of  the 74 

Tibia,  views  and  description  of  the  (PL  XLV) 141,142 

Tillodoutia,  characters  of  the 9 

Tillotherium,   occurrence  of,   with  Dinocerata   re- 
mains  -  9 

Tinoceras,  place  of,  among  Dinocerata 10 

variation  of  premaxillaries  in 24 

incisors  of 43 

upper  canines  of - 46 

lower  molar  teeth  of 51 

brain  of 56 

characters  of-.. 191 

list  of  species  of,  with  account  of  specimens 20f-218 

Tinoceras  alfine,  view  of  skull  of 19 

description  of  specimen  of 204, 205 

Tinoceras  anceps,  views  of  first  dorsal  vertebra  of..  80 

measurements  of  first  dorsal  veitebra  of 81 

description  of  specimens  of 202,203 

Tinoceras  and  Dinoceras,  comparison  of  second  and 

third  dorsal  veitebra  in 82,83 

comparison  of  pelvic  arch  in 137 

restorations  of  (PL  LV,  LVI) 165-168 

Tinoceras  annectens,  view  of  nasals  of 13 

view  of  skull  of 21 

views  of  lowtr  jaw  of 36 

description  of  specimen  of 205, 206 

Tinoceras  cornutum,  description  of  specimens  of...  206-208 

Tinoceras  crassifrona,  view  of  skull  of 29 

description  ot  specimen  of 208,  209 

Tinoceras  galeatum,  description  of  specimen  of 209 

Tinoceras  grande,  view  of  skull  of 21 

palate  of 30 

view  of  upper  canines  of 44 


IJTDEX. 


243 


Page, 
rinoceras  p-amlc — Coutiuucd. 

views  of  atlas  of  .71 

views  and  measurements  of  foui  tli  cervical  ver- 
tebra of 7J 

description  of  specimens  of 210 

Tinoceras  bians,  view  of  skull  of 30 

description  of  specimen  of 210,  211 

Tinoceras  ingtns,  views  and  descriptions  of  skull  of 

(PL  XV,  XVI,  X VH) 14,  IG,  19,  27 

occiput  of 20 

view  of  palate  of 25,30 

nasal  bones  of 31 

measurements  of  skull  of 33 

view  of  upper  canine  of 45 

views  and  description  of  teeth  of  (PI.  XVIII) .  .45, 46, 49 

upper  molar  series  of 49 

views  of  brain  cavity  of 55 

'views  of  left  lunar  of 105 

measurements  ot  rigbt  and  left  lunars  of lOG 

view  and  measurements  of  left  pyramidal  of,...  108, 109 

measurements  of  right  trapezium  of Ill 

measurements  of  rij2:bt  trapezoid  of 113 

view  of  right  unciform  of 119 

measurement  s  of  right  unciform  of 120 

measurements  of  fourth  metacarpal  of 126 

views  of  pelvis  of 136 

measurements  of  pelvis  of 137, 138 

view  of  left  astragalus  of 149 

measurements  of  left  astragalus  of 151 

view  and  description  of  restoration  of  (PI.  LVI)         165 

size  of .' 166, 168 

description  of  specimen  of 211 

Tinoceras  jiigum,  description  of  specimen  of   212 

Tinoceras  lacustre,  description  of  specimen  of 212,213 

Tinoceras  latum,  description  of  specimens  of .  - .   ...  213, 214 
Tinoceras   longiceps,   view  and    measurements   of 

lower  jaw  of 37, 40 

'  view  of  upper  canine  of 43 

description  of  specimen  of 214, 215 

Tinoceras  pugnas,  nasals  of 13,  3 1 

view  of  skull  of .19,21,27,63 

occiput  of 20 

view  of  palate  of 25 

measurements  of  skull  of 33 

views  and  descriptions  of  lower  jaw  and  teeth  of 

(P1.XIX) 35,41 

view  of  upper  canine  of 45 

description  of  specimen  of 215,216 

Tinoceras  Speirianum,  description  of  specimen  of. ..  21G 

Tinoceras  stenops,  view  of  upper  molar  series  of 47 

description  of  specimen  of 217,  218 

Tinoceras  vagansi,  view  of  skull  of 17 

description  of  sptcimen  of 218 

TinoceratidsB,  species  of 191 

Tomes,  C.  S.,  publications  of,  respectiog  Dinocerata.  236 


Page. 
Trapezium  and  trapezoid,  views  and  description  of 

(PI.  XXXIII) 110-111 

Tria^sic  and  Jurassic  mammals,  studies  of,  by  0.  C. 

M:.ish 169 

U. 

Uiutatherium.  place  of,  among  Dinocerata 10 

nasal  bones  of .  31 

dentition  of 41 

premolars  in  lower  jaw  of   49 

■   brain  of   56 

chaiatters  of        191 

list  of  species  of,  with  account  of  specimens 219-222 

Uintatberium  fissideus,  desciiplion  of  specimen  of..  220 

Uiutatherium  lalifrous,  view  of  skull  of 17 

views  and  measurements  of  second  rib  of 130, 132 

description  of  specimen  of 220,221 

Uintaiheiium  Leidianum,  description  of  specimen  of  221, 222 

Uiutatherium,  robustum,  lowerjawof 38 

views  of  brain  cavity  of  . 57 

de.scription  of  specimen  of 219 

Uiutatherium  segue,   views  and  measurements  of 

lower  jaw  of 39,  40 

views  of  third  dorsal  vertebra  of 83 

description  of  specimen  of 222 

Uinta  Utes,  hostility  of 2 

Ulna,  views  and  description  of  the  (PL  XXX) 96-99 

Unciform  and  magnum, views  and  description  of  the 

(PI.  XXXIV) 117-120 

Ungulates,  genealogy  i  f  the .■ 17J-170 

classification  of  Ihe 176-178 

modificationof  loot  in  the 181-189 

Upper  molars,  description  of  the 48, 49 

Upper  premolars,  description  of  the 46-48 

V. 

Vermilion  Creek  Group 5,6 

Vertebrae,     views     and     description    of    the    (PI. 

XII-XXVI,  XLIII) 69-86 

Vomers,  description  of  the 32 

W. 

Wann,  \V.  N.,  collection  of  specimens  by 203 

Wasatch  Group 5,  fl 

Wicks,  F.  S.,  collection  of  specimens  by 195 

Williston,  S.  W.,  acknowledgment  of  aid  of xviii 

Wortmau,  J.  L.,  collection  of  specimen  by 220 

publications  of,  respecting  Dinocerata 236 

Wyoming,  sil  nation  and  dtscripliou  of  ancient  lake 

basin  in,  containing  Dinocerata  remains 1,2 

localities  in,    from    which  Dinocerata  remains 

have  come 8 

T. 
Yale  Collie,  Dinocerata  specimens  in  museum  at..  4 
Yale  College  expeditions,  acknowledgments  to  mem- 
bers of XVIII 


PLATE  I. 


PL^TE    1. 

DINOCERATA. 

Skull  of  DiNOCERAS  MIRABILE,  Marsh. 

Two-fifths  Natural  Size. 
Skull ;  obliaue  view,  type  specimen   (No.  1 03G,  Yale  College  Museum,) il 

This  skull,  from  which  the  figures  on  the  next  six  plates  are  also  drawn,  belonged  to 
an  animal  fully  adult,  as  shown  by  the  teeth,  but  not  so  old  as  to  have  the  cranial  sutures 
obliterated.     The  right  canine  is  restored  from  the  left,  which  is  perfect. 


PLATE   I 


E  Cnfland.  lith  N»i«r  Haven 


DINOCERAS   MIRABILE,  Marsh  % 


PLATE    II. 


P^L^TE    II. 

DINOCERATA. 
Skull  of  DiNOCERAS  MIRABILE,  Marsh. 

One-fourth  Natural  Size.  Pa^e. 

iSkull ;  lateral  view,  seen  from  the  left, 11 

n    — Nasal  boiie. 
pm — Premaxillary. 
c    — Canine  tooth, 
m  • — Maxillary  bone. 
m'  — Maxillary  protuberance. 
I    — Lachrymal  bone. 
/   —Frontal. 
ma — Malar. 
pi  — Palatine. 
pt  — Pterygoid. 
as  — Alisphenoid. 

s    — Post-glenoid  process  of  squamosal. 
hs  — Basisphenoid. 
ho  — Basioccipital. 
o    — Occipital  condyle. 
p    — ^Posterior  crest. 
p'  — Posterior  jjrotuberance. 


PLATE   E. 


U 
I — I 

% 

O 

Q 

H 

> 
CD 


I — I 


PLATE  III. 


p^la^tp::  hi. 

DINOCERATA. 

Skull  of  DiNOCERAS  MiRABiLE,  Marsh. 

One-fourth  Natural  Size,  Page. 

Skull ;  front  view, ._ -- 11 

NOTK. — The  surface  covered  by  oblique  bars  in  this  and  tlio  following  plates  indicates  portions  concealed  by 
the  adhering  matrix  or  otherwise  obscured. 


PLATE    III. 


F  Berger,  del 


E.Crisand,  lith- New  Haven. 


DINOGERAS   MIRABILE,  Marsli.  ^A. 


PLATE   IV. 


JPLA.TE    lA^. 

DINOCERATA. 
Skull  of  DiNOCiiKAS  MiKABiLE,  Marsli. 

One-fourth  Natural  Size.  Pa^o 

Skull;  superior  view, 11 


PLATE  ly 


b 

3 
o 

o 
m 


I — I 


I 


PLATE   V. 


DINOCERATA. 
Skull  of  DiNOCERAS  MiRABiLE,  Marsh. 

One-fourth  Natural  Size.  P:i..e 

Skull;  inferior  view,  .... 24 

n   ■ — Nasal  bone. 

■pm — Premaxillary. 

c    — Canine  tooth. 

ni  — Maxillary  bone.  .     . 

>w'  — Maxillary  protuberance. 

ma — Malar  bone. 

pi  — Palatine. 

pt  — ^Pterygoid. 

s    — ^Post-glenoid  process  of  squamosal. 

0    — Occipital  condyle. 

p    — Posterior  crest. 

p'   — Posterior  protuberance, 


PLATE    V 


u 

I— I 

o 
o 

> 


I— I 


t^ 


PLATE   VI. 


DINOCERATA. 

Bram-cast  of  Dinoceras  mikabile,  Marsh. 

Three-fourths  Natural  Size.  Pafe. 

Fig.  1. — Cast  of  Brain-cavity ;  lateral  view,  seen  from  the  left, 53 

Fig.  2. — The  same;  superior  view, 54 

Fig.  3. — The  same;  inferior  view, ■    55 

ol  or  I- — Olfactory  lobes, 
c    — Cerebral  hemispheres. 
s    — Sylvian  fissure. 
op  or  II- — Optic  nerves. 
V  — Trigeminal,  or  fifth,  nerve 
P  — Pituitary  body. 
f  — Flocculus. 
f  — Sixth  nerve. 
cb  — Cerebellum. 

cf  or  XII — Condylar  foramen  for  twelfth  nerve. 
m  —Medulla. 


PLATE  VI. 


.-^>s6!w  «?■  .  '-^  ^s^ 


f^Sl%i  ,_ff^'T^'>^, 


O/? 


.Cb 


XII.. 


E.Crisand.  .del. 


:,Orisand  lith.NevL'Ka-ven 


DINOCERAS   MIRABILE,  Marsh.-A 


PLATE   VII 


DINOCERATA. 
Molars  of  Dinocekas  mikabile,  Marsh. 

Natural  Size,  Page. 

Pig.   1. — Upper  molars;  exterior  view,  from  left  side, -_ 46 

Fi^s.  2. — The  same ;  showing  grinding  surface, — 48 


PLATE    VII. 


'  / 


J 


J 


^J     V/ 


F  Berger,del. 


E.Crisand,  lith.  New  Haven. 


DINOCERAS   MIRABILE,  Marsh.  Vi 


VTE    Vir 


PLATE    VIII. 


DINOCERATA. 

Lower  jaw  and  teeth  of  Dixocekas  mirabile,  Marsh.  Fan'-- 

Fig.   1. — Right  lower  jaw;  lateral  view,  inner  side,  one-third  natural  size, 49 

i  — First  incisor  tooth. 

G  — Canine  tooth. 

d  — Diastema. 

s  —  Section  through  symphysis. 

cp  — Process  for  protection  of  canine  tusk. 

a  — Angle  of  jaw. 

y  — Dental  foramen. 

cd  — Condyle. 

cr  ■ — Coronoid  process. 

Fig.   2. — Left  lower  molars;    superior  view,  natural  size,. 50 

Fig.  3. — The  same;  lateral  view,  natural  size, _ . 50 

l/»»? — First  premolar. 
Ini   — First  molar. 

The  first  and  second  premolars  in  figures  2  and  3  are  restored  from  a  second  sjjecimen. 


PLATE  vnr. 


X 


F.Berger,del. 


E  Gnsand,  lith  NewHavo 


DINOCERAS   MIRABILE,  Marsh. 


PLATE   IX. 


DINOCERATA. 
Teeth  of  Dinoceras  lucare,  Marsh. 

Natural  Size.  Page. 

Fig.   1. — Upper  molars  and  canine;  type  specimen,  (No.  1038,)  lateral  view,  seen  from  the  left,     45 

Fig.  2. — Upper  molars ;  showing  grinding  surface, 49 

c    — Canine  tooth. 

d   — Diastema. 

Ip  — First  premolar. 

\m — First  molar. 
f  — Posterior  palatine  foramen. 
f  — Palato-maxillary  foramen. 


PLATE  IX 


E  Cnsar.d  Uth  New  Haver. 


DINOCERAS  LUCARE,  Marcli  H 


PLATE   X. 


DINOCERATA. 
Skull  of  DiNOCERAS  LATiCEPS,  Marsh 

One-fourth  Natural  Size.  Pane, 

Skull;  type  specimen,  (No.  1039,)  lateral  view,  seen  from  the  left, 26 


PLATE  X. 


o 

5 
o 

Q 
> 

> 

H 
O 


PLATE    XI. 


DINOCERATA. 
Skull  of  DiNOCERAS  LATiCEPS,  Marsh. 

One-fourth  Natural  Size,  Page, 

Skull;  (No.  1039,)  superior  view, 26 


PLATE   XI. 


2 
O 
Q 

> 
U] 

> 

l-H 

o 


PLATE   XII. 


DmoCERATA. 
Lo-ro-er  jaw  of  Dinoceras  laticeps,  Marsh. 

One-third  Natural  Size.  _  Pace, 

Fig.   1. — Lower  jaw;  (Xo.  1039,)  superior  view, __  _  35 

Fig.  2. — The  same;  front  view, _       g^ 


PLATE  XTl. 


E.Cnsand,  lith.  New  Haven. 


DINOCERAS    LATIC EPS,  Marsh.  Vs. 


PLATE   XIII. 


PL^TE    XIII. 

DINOCERATA. 
Lower  jaw  of  Dinogeras  laticeps,  Marsh. 

One-third  Natural  Size.  Pngi'. 

Fig.  1. — Lower  jaw;  (No.  1039,)  seen  from  tlie  left, 35 

Fig.  2. — Lower  jaw;  posterior  view, 35 

c  — Socket  for  canine  tooth. 
m — Mental  foramen. 

p  — Process  for  protection  of  canine  tusk. 
a  — Angle  of  jaw. 
cd — Condyle. 
cr — Coronoid  process, 
d  — Dental  foramen. 
S  — Symphysis. 


PLATE  xnr. 


P  Berger,  del 


E.Cnsand,  lich  New- Haven. 


DINOCERAS    LATICEPS,  Marsh   Vs. 


xr 


PLATE    XIV. 


DINOCERATA. 
Skull  of  DiNOCERAS  LATICEPS,  Marsli,    (female.) 

One-fourth  Natural  Size.  P:igi' 

Fig.   1.— Skull;  (No.  1202,)  lateral  view,  seen  from  the  left    _ 45 

Fig.  2. — The  same;  superior  view, 45 

c  — Canine  tusk. 

m! — Maxillary  protuberance. 

p'  — Posterior  protuberance- 


PLATE  XIV: 


2 
O 
O 

> 
w 

> 

O 


^ 


PLATE    XV. 


DINOCERATA. 
Skull  of  TiNOGERAS  iNGENS,  Marsh. 

One-fourth  Natural  Size.  Page. 

Skull;  type  specimen,  (No.  1041,)  lateral  view,  seen  from  the  left, 14 


PLATE  XV: 


5 

o 
o 

M 

> 

z 

o 

en 


/■ 


PLATE    XVI 


DINOCERATA. 
Skull  of  TiNOCERAS  INGENS,  Mai'sh. 

One-fourth  Natural  Size.  Page, 

Skull;   (Xo.  1041,)  front  view,-    14 


PLATE  XVI. 


E.  Grisand,  lich.  Kew  Haven. 


TINOCERAS    INGENS,  Marsh.  y4_ 


PLATE   XYII 


DINOCERATA. 
Skull  of  TiNOCERAS  INGENS,  Marsh. 

One-fourth  Natural  Size.  Pat^e. 

Skull;  (No.  1041,)  superior  view, ^ 16 


PLATE  XVH. 


5 

o 
n 

> 
o 

GO 


•CS^'CH      _ 


PLATE    XVIII. 


PL^TE  :s:v^iii. 

DINOCERATA. 
Teeth  of  Tinoceras  ingens,  Marsh. 

Natural  Size.  Page, 

Fig.   1. — Upper  molars;  (No.  1041,)  left  side,  lateral  view,  seen  from  the  left, 40 

Fig.  2. — The  same ;  showing  grinding  surface, 46 


PLATE  XVIII. 


a 
en 


^^'  T-^^^ 


PLATE    XIX 


DINOCERATA. 

Lo-wer  jaw  and  teeth  of  Tinocekas  pugnax,  Marsh.  i.;,„c. 

Fig.   1. — Lower  jaw;  lateral  view,  seen  from  the  left,  oue-third  natural  size, 35 

i  — Incisor'tooth. 

c  — Canine  tooth. 

d  — Diastema. 

f  — Mental  foramen. 

cp  — Process  for  j)rotectiou  of  canine  tusk. 

a  — Angle  of  the  jaw. 

cd    — Condyle. 

cr  — Coi'onoid  process. 

Fig.  2. — Lower  molars;  superior  view,  natui-al  size, 41 

Fig.  3. — The  same ;  lateral  view,  natural  size, 41 

Ijjni — First  premolar 
lin  — First  molar. 


PLATE  XIX. 


cd 


F  Bsrger,  del 


E  Criaajid.  lich  New  Haven. 


TINOCERAS  PUGNAX,  Marsh. 


PLATE    XX 


PLATE  xx:. 

DINOCERATA. 
Atlas  of  DiNOCEKAS  MIR  A  BILE,  Marsh. 

One-fourth  Natural  Size.  P-pm' 

Fig.  1. — Atlas;  lateral  view,  seen  from  the  left, __  C9 

Fig.  2. — The  same;  superior  view, 09 

Fig.  3. — The  same;  anterior  view, 09 

Fig.  4. — The  same;  inferior  view, 09 

Fig.  5. — The  same;  posterior  view, G9 


PLATE  XX. 


■F  Bsrger.del, 


E.Orisand,  lith-Ne-w Haven. 


DINOCERAS   MIRABILE,  Maxsh.  V^. 


PLATE    XXI. 


DINOCERATA. 
Axis  of  DiNOCERAS  MiRABiLE,  Marsh. 

One-fourth  Natural  Size.  Pa^f. 

Fig.  1. — Axis;  lateral  view,  seen  from  the  left,  ._• 72 

Fig.  2. — The  same ;  superior  view, _. 72 

Fig.  3. — The  same;  anterior  view, ■ 72 

Fig.  4. — The  same;  inferior  view, . . _  72 

Fig.  5. — The  same;  posterior  view, _._ 72 


PLATE   XXT. 


F  Berger,  del 


E.Cnsand,  lith. Ne"w Haven. 


DINOCERAS   MIRABILE,  Marsh.  V4. 


PLATE    XXII. 


DmOCERATA. 

Cervical  Vertebrae  of  Dinoceras  mirabile,  Marsh. 

One-fourth  Natural  Size.  Page. 

Fig.     1. — Third  cervical  vertebra;  lateral  view,  seen  from  tlie  left, 74: 

Fig.     2. — The  same;  superior  view, .  74 

Fig.     3. — The  same;  anterior  view, ■ 74 

Fig.     4. — The  same;  inferior  view, 74 

Fig.     6. — The  same;  posterior  view, 74 

Fig.     6. — Seventh  cervical  vertebra ;  lateral  view,  seen  from  the  left, 78 

Fig.     1. — The  same ;  superior  view, 78 

Fig.     8. — The  same;  anterior  view, 78 

Fig.     9. — The  same;  inferior  view, -  -  78 

Fig.   10. — The  same;  posterior  view, 78 


PLATE    XXTL 


F  Berger.del 


E.Crisand,  lith.  New  Haven. 


DINOCERAS   MIRABILE,  Marsh.  V^. 


PLATE    XXIII. 


DIlSrOCERATA. 

Dorsal  Vertebra  of  Diin'OCERAS  mirabile,  Marsh. 

One-fourth  Natural  Size.  Pace. 

Fig.  1. — Secoud  dorsal  vertebra;  lateral  view,  seen  fi-om  the  left, S2 

Fig.  2. — The  same ;  superior  view, --. 82 

Fig.   3. — The  same ;  anterior  view, —  S3 

Fig.  4. — ^The  same ;  inferior  view,  ..  . 82 

Fig.  5. — The  same;  posterior  view, 82 


PLATE   XXIIT. 


F  Berger,  del 


E.Crisand,  lith.  New  Haven. 


DINOCERAS   MIRABILE,  Marsli.  V^. 


PLATE    XXIY. 


DINOCERATA. 

Dorsal  Vertebrae  of  Dinoceras  mirabile,  Marsh. 

One-fourth  Natural  Size.  Page. 

Fig.  1.— Median  dorsal  vertebra;  latei-al  view,  seen  from  tlie  left, 84 

Fig.  2. — The  same;  anterior  view, -- 84 

Fig.  3. — The  same;  inferior  view, 84 

Fig.  4. — The  same ;  posterior  view, 84 

Fig.  5. — Last  dorsal  vertebra;  lateral  view,  seen  from  the  left, 84 

Fig.  6. — The  same ;  superior  view, 84 

Fig.  1. — The  same ;  anterior  view, 84 

YiG,   8. — The  same ;  inferior  view, 84 

Fig.  9. — The  same ;  posterior  view,  _ 84 


PLATE    XXIV 


F  BoTgei,  del 


£  Cnsand,  lith  New  Haven. 


DINOCERAS   MIRABILE,  Marsh.  V^. 


PLATE    XXY. 


DINOCERATA. 
Lumbar  Vertebras  of  Dinoceras  mikabile,  Marsh. 

One-fourth  Natural  Size.  Pa"^e. 

Fig.     1. — Lumbar  vertebra,  fourth  from  sacrum ;  Literal  view, 85 

Fui.     2. — The  same ;  superior  view, 85 

Fig.     3. — The  same;  anterior  view, 85 

Fig.     4. — The  same;  inferior  view, 85 

Fig.     5. — The  same;  posterior  view, 85 

Fig.     6. — Lumbar  vertebra,  third  from  sacrum;  Lateral  view, 85 

Fig.     T. — The  same;  suj^erior  view, 85 

Fig.     8. — The  same ;  anterior  view, ■ 85 

Fig.     9. — The  same ;  inferior  view, -   85 

Fig.   10. — The  same;  posterior  view, - 85 


PLATE    XXV" 


■^""^   3 


T\  Crieynri,  lith  Nnw  ffn; 


DINOCERAS   MIRABILE,  Marsh.  V^. 


PLATE   XXVI. 


DINOCERATA. 
Lumbar  Vertebrae  of  Di]s'ocek.\s  mikabile,  Marsh. 

One-fourth  Natural  Size.  Page, 

Fig.      1. — Lvimbar  vertebra,  second  from  sacrum;  lateral  view,  seen  from  the  left, 85 

Fig.     -2. — The  same;  superior  view, , S5 

Fig.     3. — The  same;  anterior  view, . S5 

Fig.     4. — The  same;  inferior  view, 85 

Fig.     5. — The  same;  jjosterior  view, _..__  85 

Fig.     6. — Last  lumbar  vertebra;  lateral  view,  seen  from  the  left, 85 

Fig.     7. — The  same;  superior  view, . 85 

Fig.     S. — The  same ;  anterior  view, 85 

Fig.     9. — The  same;  inferior  view, 85 

Fig.   10. — Tlie  same;  jiosterior  view, ._.. 85 


P'LATE   XXVT. 


Fi'^orgei.del 


E-Crisand,  ]ich  New  Haven 


DINOCERAS   MIRABILE,  Marsh^  V^. 


PLATE    XXVII. 


DINOCERATA. 
Left  Scapula  of  Dinoceras  mirabile,  Marsh. 

One-fourth  Natural  Size.  Pai^e. 

Fig.  1. — Scajjnla ;  exterior  view, 87 

cb — Coracoid  border, 
c  — Ooracoid  process. 
.170 — Glenoid  cavity. 
gh — Glenoid  border. 
ss  — Suprascapular  border. 

Fig.  2. — ITie  same;  inner  view, 87 

Fig.  3. — Tlie  same;  inferior  view, .    87 

a  — Acromion. 
s  — Spine. 


P'LATE   XX'x'11. 


E  Cnsand,  lith  Nevr  Haven 


DINOCERAS   MTRABILE,  Marsh  V^ 


PLATE    XXYIII 


DINOCERATA. 
Humervis  of  Dinoceeas  mikabile,  Marsk 

One-fourth  Natural  Size.  Page. 

Fig.  1. — Left  Humerus ;  anterior  view, .  .. 89 

]  a — Distal  end. 

Fig.  2. — Tiie  same;  inner  view, ..-    89 

Fig.  3. — The  same;  j^osterior  view, . 89 

3  a — Proximal  end. 


PLATE.  XXVIir. 


i^< 


l',.fe 


la 


E.Crisand,  lith.Nev,'- Haven. 


DINOCERAS   MIRABILE,  Marsh,  y^. 


PLATE    XXIX. 


DINOCERATA. 
Radius  of  Dixoceras  mirabile,  Marsh. 

One-fourth  Natural  Size.  Page. 

Fig.   1. — Left  Radius ;  anterior  view, 93 

1  a — Distal  end. 

Fig.  2. — -The  same;  inner  view, 93 

Fig.  3. — The  same ;  posterior  view,  showing  surface  apjjlied  to  ulna, 93 

3a — Proximal  end. 

Fig.  4. — The  same;  exterior  view, . __. 93 


PLATE  XXIX, 


F  Berger,  del 


E  Cnsaild,  lith  Ne-wHavea 


DINOCERAS   MIRABILE,  Marsh  V^ 


PLATE    XXX. 


DINOCERATA. 
Ulna  of  DiNOCERAS  MiiiABiLE,  Marsh. 

One-fourth  Natural  Size.  Page. 

Fig.  1 . — Left  Ulna ;  anterior  view,  showing  radial  surface, 96 

la — Distal  end. 

Fig.  2. — The  same ;  inner  view, ...    96 

Fig.   3. — The  same;  posterior  viev/. 96 

Fig.  4. — The  same;  outer  view, 96 


PLATE   XXX. 


^1 


IX      i/ 


a. 


^, 


\.  //,,,/ 


F  Bergei,  del 


E  Crisand,  Uth  New  Haver 


DINOCERAS   MIRABILE,  Marsh.  V4. 


PLATE    XXXI. 


DINOCERATA. 
Scaphoid  and  Lunar  of  Dinoceras  mirabile,  Marsh.     (Left  foot.) 

One-half  Natural  Size.  Pan-e. 

Pig.     1. — Scaphoid;  outer  view, 102 

Fig.     2. — The  same ;  posterior  view, 10f> 

Fig.     3. — The  same ;  inner  view,  showing  face  adjoining  hmar, . .  102 

Fig.     4. — The  same ;  anterior  view, 102 

Fig.     5. — The  same ;  i^roximal  view,  showing  face  for  radius, 102 

Fig.     6. — The  same;  distal  view,  showing  faces  for  trapezium  and  trapezoid, 102 

Fig.     v. — Lunar;  anterior  or  outer  view,  104 

Fig.     8. — The  same;  lateral  view,  showing  face  adjoining  scaphoid, 104 

Fig.     9.-^The  same ;  posterior,  or  palmar,  view, 104 

Fig.  10. — The  same;  lateral  view,  showing  face  adjoining  j^yramidal,. , 104 

FiG.   1 1. — The  same;  proximal  view,  showing  face  for  radius, 104 

Fig.   12. — The  same;  distal  view,  showing  faces  for  articulation  with  magnum  and  unciform,..  104 


PLATE.  "AXXi. 


E.Crisand,  lichNewHa-ven. 


DINOCERAS   MIRABILE,  Marsli.  Vs. 


PLATE    XXXII 


PLA.TE    XXXII, 

DINOCERATA. 
Pyramidal  and  Pisiform  of  Dinoceeas  mirabile,  Marsh.     (Left  foot.) 

One-half  Natural  Size.  Page. 

YiG.     1. — Pyramidal  (or  Cuneiform)  bone;  outer  view, -. .    -. 107 

Fig.     2. — The  same;  anterior  view, 107 

Fig.     3. — The  same;  inner  view,  .showing  face  adjoining  lunar,   ...    107 

Fig.     4. — The  same ;  posterior  view, 107 

Fig.     5 — The  same;  x^roximal  view,  showing  faces  for  ulna  and  pisiform, 107 

YiG.     6. — The  same ;  distal  view,  showing  faces  for  unciform  and  for  fifth  metacarpal, 107 

Fig.     7. — Pisiform;  anterior  view, 109 

Fig.     8.— The  same;  inner  view,  showing  ai'ticulation  with  pyramidal,- . 109 

Fig.     9. — The  same;  posterior  view, 109 

Fig.   10. — The  same;  outer  view, 109 

Fig.   1 1 . — The  same ;  proximal  view,  showing  articulation  with  ulna, 109 

Fig.  1 2. — The  same ;  distal  view, 109 


PLATE    XXXn. 


10 


11 


JL.Orisancl,  lich.Ne'wHa: 


DINOCERAS   MIRABILE,  Marsh.  1/2. 


PLATE    XXXIII. 


PJLA.TE  x:x:x:iii. 

DINOCERATA. 

Trapezium  and  Trapezoid  of  Dikoceeas  mirabile,  Marsh.     (Left  foot.) 

One-half  Natural  Size.  Page. 

Fig.     1. — Trapezium;  lateral  view,  showing  outer  surface, 110 

Fig.     2.— The  same;  jDosterior  view, -  110 

Fig.     3. — The  same;  lateral  view,  showing  inner  surface,  articulating  with  trapezoid, 110 

Fig.     4. — The  same;  anterior  view, .    .    -  110 

Fig.     5. — The  same ;  proximal  view,  showing  articulation  with  scaphoid, 110 

Fig.     6. — The  same ;  distal  view,  showing  metacarpal  articulation, 110 

Fig.     7. — Trapezoid;  front  view,  showing  external  surface, 111 

Fig.     8. — The  same;  lateral  view,  showing  face  adjoining  trajjezium,  _. 111 

Fig.     9. — The  same ;  posterior  view, —  i 111 

Fig.  10. — The  same;  lateral  view,  showing  face  adjoining  magnum, Ill 

Fig.  11. — The  same ;  proximal  view,  showing  articulation  with  scaphoid, 111 

Fig.   12. — The  same;  distal  view,  showing  metacarpal  articulation, HI 


PLATE.  XXXIir. 


12 


E.Crisand,  lith  New  Haven. 


DINOCERAS   MIRABILE,  Marsh.  Vs. 


PLATE    XXXIV. 


Fig.  1.- 

FlG.  2.- 

FlG.  3.- 

FiG.  4.- 

FlG.  5.- 

FlG.  6- 

FlG.  1.- 

FlG.  8.- 

FlG.  9.- 

FiG.  10.- 

FlG.  11.- 

FlG.  12.- 


DINOCERATA. 
Magnum  and  Unciform  of  Dinoceras  mieabile,  Marsh.     (Left  foot.) 

One-half  Natural  Size.  Paee 

IMagnum ;  front  view,  stowing  external  surface, 113 

The  same ;  lateral  view,  showing  face  adjoining  trapezoid, 113 

posterior,  or  palmar,  view, 113 

lateral  view,  showing  face  adjoining  unciform, 113 

superior,  or  proximal,  view, II3 

inferior,  or  distal,  view,  showing  face  for  metacarpal  articulation, 113 

lateral  view,  showing  external  surface, __  117 

front  view,  showing  face  adjoining  magnum, 117 

lateral  view,  showing  inner  surface, _  117 

posterior  view, 117 

superior,  or  proximal,  view,  showing  faces  for  lunar  and  pyramidal, 117 

inferior,  or  distal,  surface  for  metacarpal  articulations, Hi 


-The  same 
-The  same 
-The  same 
-The  same 
-Unciform 
-The  same 
-The  same 
-The  same 
-The  same 
-The  same 


PLATE,  ijxxrv: 


10 


11 


12 


E.Criaand,  lith.  TTevr  Haver.. 


DINOCERAS   MIRABILE,  Marsh.  %. 


PLATE    XXXV 


DINOCERATA. 

Metacarpals  of  Dinocekas    mirabile,  Marsh.     (Left  foot.) 

One-half  Natural  Size.  p„„ 

Fig.     1. — First  metacarpal;  front  view, -jo-i 

Fig.     2. — The  same ;  lateral  view,  showing  inner,  or  tibial,  side, 121 

Fig.     3. — The  same ;  posterior,  or  palmai",  view, jo^ 

Fig.     4. — The  same;  lateral  view,  showing  outer,  or  ulnar,  side, 12L 

Fig.     5. — The  same;  proximal  end, j21 

Fig.     6. — The  same;  distal  end, .  _ jo^ 

Fig.     v. — Second  metacarpal ;  front  view, 122 

Fig.     8. — The  same ;  lateral  view,  showing  inner,  or  radial,  side, 122 

Fig.     9. — The  same;  posterior,  or  palmar,  view, 122 

Fig.   1 0. — The  same ;  lateral  view,  showing  outer,  or  ulnar,  side, 122 

Fig.  1 1. — The  same ;  proximal  end, 122 

Fig.  1 2. — The  same ;  distal  end, 122 


PLATE    XXXV: 


12 


F  Berg'ei,  del 


E.Crisand,  lith. New Ha-ven. 


DINOCERAS   MIRABILE,  Marsh.  Va. 


PLATE    XXXYI. 


Fig. 

1 

Fig. 

■2 

Fig. 

3 

Fig. 

4 

Fig. 

5 

Fig. 

6. 

Fig. 

7. 

Fig. 

8 

Fig. 

9 

DINOCERATA. 
Metacarpals  of  Dinoceras  mibabile    Marsh.     (Left  foot.) 

One-half  Natural  Size.  Page. 

-Third  metacarpal;  front  view, 123 

-The  same;  lateral  view,  inner,  or  radial,  side, •_ 123 

-The  same ;  posterior  view, 123 

-The  same;  lateral  view,  outer,  or  ulnar,  side, i . 123 

-The  same ;  proximal  end, J23 

-The  same ;  distal  end, 123 

-Fourth  metacarpal ;  front  view, 124 

-The  same ;  lateral  view,  inner,  or  radial,  side, 124 

-The  same;  distal  end, 124 


PLATE  XXXVI. 


•f'> 


'•''''^■'"' 


F  Berber,  del. 


E-Onsand,  lith.  New  Haven- 


DINOCERAS    MIRABILE,   Marslt  >2 


PLATE    XXXYII 


JPLA.TE    XXXA^II. 

DIlsrOCERATA. 
Metacarpals  of  Dinoceras  mirabile,  Marsh.     (Left  foot.) 

One-half  Natural  Size.  Page. 

Fig.  1. — Fourth  metacarpal ;  j)osterior,  or  palmar,  view, 124 

Fig.  2. — The  same;  lateral  view,  showing  outer,  or  ulnar,  side, -.  124 

Fig.  3. — The  same;  proximal  end, 124 

Fig.  4. — Fifth  metacarpal;  front  view, .--- 127 

Fig.  5. — The  same ;  lateral  view,  showing  inner,  or  radial,  side. —  127 

Fig.  6. — The  same;  posterior,  or  palmar,  view, 127 

Fig.  7. — The  same;  lateral  view,  showing  ulnar  side, 127 

Fig.   8. — The  same;  proximal  end, 127 

Fig.  9. — The  same;  distal  end, 127 


PLATE    XXXVIl 


v;<4).^ 


F.Berger,  del. 


E-Crisand,  ]uh  NewHaveTi 


DINOGERAS   MIRABILE,  Marsh  Vz. 


PLATE    XXXVIII. 


DINOCERATA. 
Phalanges  of  Dinoceras  mirabile,  Marsh. 

Page. 
One-half  Natural  Size. 

Fig.  1. — Proximal  phalanx  of  a  median  digit;  front  view, 127 

la — Lateral  view. 
lb — Posterior  view. 
Ic — Proximal  end. 
Id — Distal  end. 

Fig.  2. — Proximal  ijhalans  of  a  lateral  digit;  front  view, 127 

2a — Lateral  view. 
2b — Posterior  view. 
2c — Proximal  end. 
2d — Distal  end. 

Fig.  8. — Median  phalanx;  front  view, 128 

Sa — Posterior  view. 
3b — Proximal  end. 
So — Distal  end. 

Fig.  4. — Median  phalanx;  front  vieWj . 128 

4a — Lateral  view. 
45 — Posterior  view. 
4c — Proximal  end. 
4c?— Distal  end. 

Fig.  5- — Ungual  phalanx  of  median  digit;  front  view, 128 

5a — Posterior  view. 
5b — Proximal  end. 
5c — Distal  end. 

Fig.  6. — Ungual  phalanx  of  lateral  digit;  front  view, 128 

6a — Lateral  view. 
6b — Posterior  view. 
Qc — Proximal  end. 
6d — Distal  end. 

'PxG.  7. — Sesamoid  bone  from  metacarj^o-phalangeal  articulation;  lateral  view, 121 

7a — Articular  surface. 


PLATE  xxxvnr. 


/a 


n 


fc 


2h 


2d 


Jh 


n 


^Oi 


^rf 


Ji 


6 
6d 


6a 


6c 


Y  Eerg'er,  del. 


E.Cnaand,  lith.Ne^Ha.veii. 


DINOGERAS   MIRABILE,  Marsh  1/2. 


PLATE    XXXIX 


li^L^TE    XXXIX. 

DINOCERATA. 
Ribs  of  DiNOCERAS  MiRABiLE,  Marsh. 

One-fourth  Natural  Size.  Pai't 

Fig.  1. — First  rib ;  anterior  view, 129 

Fig.  2. — The  same;  inner  view, . ._.-  129 

Fig.  3. — The  same;  superior  view,  showing  head  and  tubercle, ... 129 

Fig.  4. — Dorsal  rib ;  posterior  view, 133 

Fig.  5. — The  same ;  inner  view, 133 

Fig.  6. — The  same;  superior  view,  showing  head  and  tubercle, 133 

Fig.  7. — Posterior  rib ;  anterior  view, 133 

Fig.  8. — The  same;  outer  view, 133 

Fig.  9. — The  same;  superior  view,  showing  head  and  tubercle,  - 133 


PLATE   1DCXIX_ 


E.Orisand,  lith  New  Haven. 


DINOCERAS   MIRABILE,  l_aTsh.  V^ 


PLATE    XL. 


DINOCERATA. 

Sternum  of  Dinocebas  mihabile,  Marsh. 

One-fourth  Natural  Size.  Page. 

Fig.     1. — First  segment;  lateral  view,  seen  from,  the  left, 133 

Fig.     2. — The  same;  superior  view, _ _ 133 

Fig.     3. — The  same ;  inferior  view, 133 

Fig.     4. — Second  segment ;  lateral  view,  seen  from  the  left, __ 134 

Fig.     5. — The  same ;  sujjerior  view, 134 

Fig.     6. — The  same;  inferior  view, 134 

Fig.     7. — Third  segment ;  lateral  view,  seen  from  the  left, 134 

Fig.     8. — The  same;  sujDerior.  view, 134 

Fig.     9. — The  same;  inferior  view, 134 

Fig.  10. — Last  segment;  lateral  view,  seen  from  the  left, 134 

Fig.  11. — The  same;  superior  view, . 134 

Fig.   12. — The  same;  inferior  view, 134 


12 


PLATE   XL_ 


10 


E.Crisand,  3ich.New-Ha-ven 


DINOCERAS   MIRABILE,  Marsh.  V^ 


PLATE    XLI 


DINOCERATA. 

Pelvis   of  DiNOCERAS   MIRABILE,   Marsh. 

One-fourth  Natural  Size.  Page. 

Fig.  1. — Pelvis;  anterior  view, 135 

Fig.   2. — The  same;  inferior  view, 135 

ffl — Acetabnlum. 
f  — Obturator  foramen. 
il — Ilium. 
is — Ischium. 
p  — Pubis. 

s  — Anterior  end  of  sacrura 
s'  — Posterior  end  of  sacrum. 


E  CnsaJid,  liih  New  Haven 


DINOCERAS   MIRABILE,  Marsh  V4 


PLATE    XLII. 


DESrOCERATA. 
Pelvis  of  DiifOCERAS  mirabile,  Marsh 

One-fourth  Natural  Size.  Pao-e. 

Fig.   1. — Pelvis;  lateral  view,  seen  from  the  left, I35 

Fig.  2. — The  same;  lateral  view,  showing  inner  sufaee, J3o 

Fig.  3. — ^The  same;  posterior  view, 235 

Fig.  4. — Sacrum;  inferior  view, . I37 

a  — ^Acetabulum. 
f — Obturator  foramen. 
i  — Sacral  face  for  ilium. 
il — Ilium. 
is — Ischium. 
p  —Pubis. 

s  — Anterior  end  of  sacrum. 
s'  — Posterior  end  of  sacrum 


r:.AT^    XiV.t. 


E  Onaani  Uch  Newfla-^ 


DINOCERAS   MIRABILE,  Marsh  Vt 


PLATE    XLIII. 


DINOCERATA. 
Caudal  Vertebrae  of  Dinoceras  laticeps,  Marsh. 

One-fourth  Natural  Size.  Page. 

Fig.  1. — First  caudal  vertebra ;  lateral  view,  seen  from  the  left, 138 

la — Superior  view. 
lb — Anterior  view. 
Ic — Inferior  view. 
1  d — Posterior  view. 

Fig.  2. — Second  caudal  vertebra;  lateral  view,  seen  from  the  left, ^..     138 

2a — Superior  view. 
2b — Anterior  view. 
2c — Inferior  view. 
2c? — Posterior  view. 

Fig.  8. — Third  caudal  vertebra ;  lateral  view,  seen  from  the  left, 138 

3a — Superior  view. 
3b — Anterior  view. 
3c — Inferior  view. 
3d — Posterior  view. 

Fig.  4. — Fourth  caudal  vertebra;  superior  view, 138 

4a — Inferior  view. 


PLATE   XLIII 


DINOCERAS   LATICEPS,  Marsh,  'A. 


PLATE    XLIY. 


DESrOCERATA. 
Femur  of  Dinoceras  mieabile,  Marsh. 

One-fourth  Natural  Size.  Page. 

Fig.  1. — Left  Femur;  front,  or  superior,  view, .. 139 

t  — Great  trochanter. 
t'  — Lesser  trochanter, 
la — Distal  end. 

Fig.  2. — The  same ;  inner  view, 139 

Fig.   3. — The  same ;  baclv,  or  inferior,  view, 139 

3ffl — Proximal  end. 


PLATE     XL  IV. 


3a 


i^-^"    'V 


E  Oi-isand,  lidl  Nevf  Hitc 


DINOCERAS   MIRABILE,  Ma.rsh. 'A, 


PLATE   XLY. 


PLA.TE    S:L^. 

DINOCERATA. 
Tibia  of  DiNOCERAs  mikabile,  Marsh. 

One-fourth  Natural  Size. 

Page. 

Fn4.  1. — Left  Tibia;  anterior  view, 141 

la — Distal  end. 

Fig.  2. — The  same;  lateral  view,  inner  side, 141 

Fig.  3. — The  same ;  posterior  view, —     141 

3a — Proximal  end. 

Fig.  4. — The  same;  lateral  view,  outer  side, -_. 141 

Fig.  5.— Section  of  shaft  of  Tibia,.. 141 


PLATE,  XLV 


3a 


P,Berg-er,del. 


E.Cnsand,  ]ith  New  Haven 


DINOCERAS   MIRABILE,  Marsh.  y4. 


PLATE    XLVI 


DINOCERATA. 
Fibula  and  Patella  of  Dinoceras  mieabile,  Marsh. 

One-fourth  Natural  Siza  Page. 

Fig.   1. — Left  Fibula;  outer  view, 143 

la — Distal  end.    . 

Fig.  2. — The  same;  posterior  view, - 143 

Fig.  3. — The  same;  inner  view, 143 

3a — Proximal  end. 

Fig.  4. — The  same;  anterior  view,    143 

Fig.  5. — Left  Patella;  front  view, 143 

Fig.  6. — The  same ;  lateral  view,  showing  inner  side, ... 143 

Fig.  7. — The  same ;  posterior  view, 143 

Fig.  8. — The  same ;  later,al  view,  showing  outer  side, 143 


PLATE   XLVl. 


3a- 


t'X 


E.Onsand,  lith  New  Haven- 


DINOGERAS   MIRABILE,  Marsh.  V^. 


PLATE   XLVII. 


DINOCERATA. 
Astragalus  of  Dinoceras  mirabile,  Marsh.     (Left  foot.) 

One-hall  Natural  Size.  Pnge. 

Fig.   1. — Astragalus ;  superior  view,  showing  face  for  articulation  with  tiliia, 14G 

P'lG.  2. — The  same;  lateral  view,  tibial  side,  _ UG 

Fig.  3. — The  same;  inferior  view, ..    140 

Fig.  4. — The  same;  lateral  view,  fibular  side, 14G 

Fig.  5. — The  same;  front  view, 14C 

Fig.  C. — The  same;  posterior  view, 140 


PLATE  XLV[[. 


~ti^^ 


'  Berger,  del 


E.Gnsand,  lith  New  Kaven. 


DINOGERAS   MIRABILE,  Marsh  Vs. 


PLATE    XLVIII 


Fig. 

1. 

Fig. 

2. 

Fig. 

3. 

Fig. 

4.- 

Fig. 

■5.- 

Fig. 

6.- 

DINOCERATA. 
Calcaneum  of  Dinoceras  mirabile,  Marsh      (Left  foot.) 

One-half  Natural  Size.  Pi"i' 

-Calcaneum;  anterior,  or  front,  view, ..    ---  151 

-The  same ;  inner  view,  tibial  side,  ._    ... . .    . 151 

-The  same;  posterior  view, ._....    -  151 

-The  same;  outer  view,  fibular  side,   151 

-The  same;  suj^erior  view,  showing  face  for  astragalus, 151 

-The  same ;  inferior,  or  jjlantar,  view, ... 151 


PLATE  XLVIII. 


P  Berger,del. 


E.  Crisand,  lith.  New  Haven- 


DINOCERAS   MIRABILE,  Marsh  Va. 


PLATE    XLIX 


DINOCERATA. 

Cuboid  and  Navicular  of  Dinocekas  mieabile,  Marsh.     (Left  foot.) 

One-half  Natural  Size.  p 

Fig.     1. — Cuboid ;  front,  or  outer,  view, jko 

Fig.     2. — The  same ;  Literal  view,  showing  face  adjoining  uavicuhar, . ^53 

Fig.     3. — The  same;  posterior,  or  plantar,  view, jr^ 

F:g.     4. — The  same;  lateral  view,  showing  fibular  side, j53 

Fig.     5. — The  same ;  proximal  surface, jijo 

Fig.     6. — The  same;  distal  surface,  supporting  fourth  and  fifth  metatarsals, 153 

Fig.'    7. — M  avicular  (or  Scaphoid) ;  front  view, -.  gr 

Fig.     8. — The  same;  lateral  view, -.-,- 

Fig.     9. — The  same;  posterior,  or  j^lantar,  view,. jk- 

Fig.  10. — The  same;  lateral  view,  showing  face  adjoining  cuboid,  _.   .. ^ ^55 

Fig.   11. — The  same;  proximal  end,  articulating  with  astragalus, 255 

Fig.   1 2.— The  same ;  distal  end,  articulating  with  cuneif ormes, I55 


PLATE  XLIX. 


^«i3»"?'''"'*=Sf"-"5!«SS^= 


•'^ 


E  Crisand,  lith  New  Haven. 


DINOCERAS   MIRABILE,  Marsh.  Vs. 


PLATE    L 


DINOCERATA. 
Tarsal  bones  of  Dimogeras  mirabile,  Marsh.     (Left  foot.) 

One-half  Natural  Size.  Page. 

Fig.      1. — Entocuneiform;  outer  vie-.v, 158 

Fig.     2. — The  same;  posterior  view, 158 

Fig.     -3. — The  same;  inner  view,  showing  face  adjoining  mesocuneiform, 158 

Fig.     4. — The  same;  anterior  view, . 158 

Fig.     5. — The  same ;  proximal  surface,  articulating  with  navicular, -  158 

Fig.     6. — The  same;  distal  surface,  supporting  first  metatarsal, 158 

Fig.     7. — Mesocuneiform;  outer,  or  front,  view, 158 

Fig.     8. — The  same;  tibial  surface,  adjoining  entocuneiform,  ..■ 158 

Fig.     9. — The  same ;  posterior,  or  plantar,  view, -.. 158 

Fig.   1 0. — The  same;  fibular  surface,  adjoining  ectocuneif orm, . 158 

Fig.   11. — The  same;  proximal  surf  ace,  articulating  with  navicular,  - 158 

Fig.   12. — The  same ;  distal  end,  supporting  second  metatarsal, 158 

Fig.   13. — Ectocuneif  orm;  outer,  or  front,  view,... .. 159 

Fig.  14. — The  same;  tibial  surface,  adjoining  mesocuneiform, 159 

Fig.  1  o. — The  same ;  posterior,  or  plantar,  view,  ..._   159 

Fig.   1 0. — The  same;  fibular  surface,  adjoining  cuboid, 159 

Fig.  1 7. — The  same ;  proximal  end,  articulating  with  navicular, 159 

Fig.  1 S. — The  same ;  distal  end,  supporting  third  metatarsal, 159 


PLATE  L 


ECrisand.  lith  Nffw  Haven. 


DINOCERAS   MIRABILE,  Ma.rsh  Vs. 


PLATE    LI 


P^L^TIll    LI. 

DINOCERATA. 
Metatarsals  of  Dinoceras  mirabile,  Marsh.     (Left  foot.) 

One-half  Natural  Size.  Pa"-e. 

Fig.      1. — First  Metatarsal;  front  view, IGl 

Fig.     2. — The  Sctme;  lateral  view,  showing  tibial  surface, .    .-^ IGl 

Fig.     3. — The  same;  posterior,  or  plantar,  view, IGl 

Fig.     4. — The  same;  lateral  view,  showing  fibular  surface, IGJ 

Fig.     5. — The  same;  proximal  end, Kil 

Fig      6. — The  same;  distal  end, —  IGl 

Fig.     7. — Second  Metatarsal;  front  view, .- IGl 

Fig.     8. — The  same;  lateral  view,  showing  tibial  surface, ......  IGl 

Fig.     9. — The  same ;  posterior,  or  plantar,  view, IGl 

Fig.   10. — The  same ;  lateral  view,  showing  fibular  surface, IGl 

Fig.  11. — The  same;  proximal  end,- -.  _ -_  161 

Fig.   12. — The  same;  distal  end, 161 

Fig.   1 3. — Third  .Metatars.il ;  front  view, 102 

Fig.   14. — The  same;  lateral  view,  showing  tibial  side, IGU 

Fig.   1 5. — The  same ;  posterior,  or  plantar,  view, 102 


PLATE  LI. 


F.  BbTger,  del. 


E-Cnsand,  litli.  NewJ 


DINOCERAS   MIRABILE,  Marsh.  Vs. 


PLATE   LII. 


PL^TE    LIT. 

DINOCERATA. 
Metatarsals  of  Dinoceras  mirabile,  Marsh.     (Lefl  foot.) 

One-half  Natural  Size.  Page. 

Fig.     1. — Third  Metatarsal;  lateral  view,  showing  fibular  surface, 162 

Fig.     2. — The  same;  proximal  end, 162 

Fig.     3. — The  same;  distal  end, . 162 

Fig.     4. — Fourth  Metatarsal;  front  view, 163 

Fig.     5. — The  same;  lateral  view,  showing  tibial  surface, 163 

Fig.     6. — The  same ;  posterior,  or  plantar,  view, 163 

Fig.     7. — The  same ;  lateral  view,  showing  fibular  surface, 163 

Fig.     8. — The  same ;  jjroximal  end, --  — 163 

Fig.     9. — The  same;  distal  end, 163 

Fig.   10.— Fifth  Metatarsal;  front  view, 163 

Fig.  11. — The  same;  lateral  view,  showing  tibial  surface, 163 

Fig.   12. — The  same;  j)osterior,  or  plantar,  view, --  163 

Fig.  13. — The  same;  lateral  view,  showing  fibular  surface, 163 

Fig.   14.— The  same;  proximal  end, 163 

Fig.  15. — The  same;  distal  end, ' 163 


PLATE  Lll. 


"  Eergex,  del. 


E.Criaand,  lith.  New  Haven. 


DINOCERAS   MIRABILE,  Marsh  y2. 


PLATE    LIII. 


i>L^TE    LIII. 

DINOCERATA. 
Phalanges  of  Dinocekas  mirabile,  Marsh. 

One-half  Natural  Size.  Page. 

Fig.     1. — Proximal  phalanx  of  raediau  digit ;  front  view, lC-4 

la  — J^ateral  view. 
15  — Posterior  view. 
Ic  — Proximal  end. 
Id  — Distal  end. 

Fig.     2. — Proximal  phalanx;  front  view, .    164 

2a  — Posterior  view. 
2b  — Proximal  end. 
2c  — Distal  end. 

Fig.     3. — Proximal  phalanx  of  lateral  digit ;  front  view, 164 

3a  — Posterior  view. 
3b  — Proximal  end. 
3c  — Distal  end. 

Fig.     4. — Median  phalanx;  front  view, 164 

4a  — Posterior  view. 
4b  — Proximal  end. 
4c  — Distal  end. 

Fig.     5. — Median  phalanx;  front  view, 164 

5a  — Proximal  end. 
5b  — Distal  end. 

Fig.     6. — Ungual  phalanx;  front  view, -  164 

6a  — Posterior  view. 
65  — Proximal  end. 
6c    ■ — Distal  end. 

Fig.     7. — Ungual  jihalanx;  front  view, - 164 

'Ja  —Posterior  view. 

75  — Proximal  end. 

7e  — Distal  end. 
Fig.     8. — Sesamoid  bone  from  metatarso-phalangeal  articulation ;  lateral  view, 164 

8a  — Articular  surface. 
Fig.     9. — Sesamoid  bone  from  metatarso-phalangeal  articulation ;  lateral  view, 164 

9a  — Articular  surface. 
Fig.   10. — Sesamoid  bone,  probably  from  hallux;  lateral  view, 164 

10a — -Articular  surface. 


il 


PLATE   Llir 


1c 


Id, 


i 


2b 


2c 


6b 


-^b 


5h 


6a 


7b 


10  a 


i9a 


fO 


8a 


E.Criaand,  lith.New Haven 


DINOCERAS  MIRABILE,  Maxsh   Vz. 


PLATE    LIY. 


DDTOCERATA. 
Feet  of  DiNOCERAS  mirabile,  Marsh. 

One-half  Natural  Size.  Page. 

YiG.   1. — Manus,  or  fore  foot  (left), 101 

s     — Scaphoid. 

I      — Lunar. 

jtj    — Pyramidal. 

tm  — Trapezium. 

/r    — Trapezoid. 

un  — Unciform. 

I    — First  digit,  or  pollex. 

rr  — Second  digit. 

/Ji— Third  digit. 

7F— Fourth  digit. 

V  —Fifth  digit. 

Fig.  2.— Pes,  or  hind  foot  (left), --     145 

a     — Astragalus. 
c      — Calcaneum. 
cb    — Cuboid. 
n     — Navicular. 
en    — Entocuneiform. 

I  — First  digit,  or  hallux. 

II  — Second  digit. 
Ill— Third  digit. 
JF— Fourth  digit. 

V  —Fifth  digit. 


PLATE   LTV 


£  Onsand.  lich  New  Ha:veTi- 


DINOCERAS   MIRABILE,  Marsh.  Vs. 


PLATE    LY. 


DINOCERATA. 

Page. 

Restoration  of  Dinoceras  mirabile,  Mtirsli.  165 

One-eighth  Natural  Size. 


n,/? 


£  Cnsand.  hth  NffwH^tv- 


DINOCERAS   MIRABILE,  Marsh  Vs_ 


PLATE   LVI. 


DINOCERATA. 

Page, 

Restoration  of  Tinoceras  ingens,  Marsh.  165 

One-sixth  Natural  Size. 


